Com port access denied windows 11. g. Explore common COM port issues ...
Com port access denied windows 11. g. Explore common COM port issues on Windows, diagnose with Serial Port Monitor, and find effective solutions quickly! Aug 8, 2025 · If you get an "Unable to open a connection to com1" message, you won't be able to use your serial port. Nov 28, 2022 · 6 Ways to Fix Drive Is Not Accessible “Access denied” in Windows 11 By Grishm Devkota Grishm Devkota Grishm holds a computer science degree and is currently employed as a Tech writer at TechNewsToday. Aug 29, 2024 · It is like the port is closed. On Win 11. Jul 2, 2023 · The issue was the FTDI board I was using had a counterfeit chip. port is a device name: depending on operating system. Opening COM3: Access denied The same situation happens when I sta Oct 16, 2020 · 5. I hate win 10 with a passion because connecting anything other than a g-d cellphone is usually an enormous exercise in frustration. when running the method below from my form. On my PC it happens 100% of the time. By following the step-by-step instructions and using tools such as PartitionAssistant Recovery, you can regain access to your USB device and retrieve any lost data. Do you have any other program open that uses the RFID device? You can check what programs use what ports using Portmon. You can clean up unused ports using Uwe Sieber's USB Cleanup program. Dec 19, 2020 · Every online discussion of COM port Access Denied errors says the same thing - make sure the COM port is not in use by another program. We can see this COM port in Windows Device Manager. How do I change COM port address or enable the advanced tab in COM port properties? 2: Use IsOpen () Function to check whether port is already opened or not. Mar 11, 2022 · To fix the error windows cannot connect to the printer access is denied, you first need to check your printer device and determine if it is caused by this error or not. Feb 24, 2024 · TPM chip inhibiting COM ports in Win 11? I have been trying to attach a USB-Serial cable to a Win 11 laptop to run a serial peripheral. Mar 12, 2024 · Does your Windows computer show External Hard Drive Access Denied error? Here's how to fix that hard drive error on Windows 10 and 11. Nov 20, 2023 · Hello All, I need your urgent Support to know how to fix the error "Access is denied" for any USB drive that I connect to any USB port in my server which has a Windows server 2022. Access is denied Software & Applications discussion , general-windows , windows-7 5 2324 April 4, 2013 Mar 14, 2026 · Users might encounter the error, “ C:\ is not accessible – Access denied ”, which prevents access to files and blocks the launch of some applications including Outlook, Office apps, web Sep 22, 2015 · Hi, after some time of flawlessly work with Arduino UNO, i've switched to a new machine (Windows 10) and I can't get it to work (previously I was using Win 7). This issue is occurring on both Windows 10 and Windows 11. May 15, 2024 · Learn how to check COM ports in Windows 11 with our detailed step-by-step guide. Jan 18, 2025 · If you need to constantly access the files, use the hidden Administrator account to make the necessary changes to your system and fix the ownership or access issue. Feb 8, 2024 · I connected the device with a CH340 RS232 to USB cable with my laptop and tried to communicate through the COM port. Nov 23, 2016 · 0 click right on this computer, go to management, device manager, com, find the port of Arduino, then go to tools and in port select the com Mar 9, 2011 · After that, it is best to uninstall the printer, browse to the first computer in Windows Explorer by entering in the address as \computername\, and then right-clicking on the printer, and choosing Connect. Whenever I try to upload a sketch, I get the following error: avrdude: ser_open(): can't open device "\\\\. I purchased a legit FTDI device but haven't bothered to make up a cable. Jan 13, 2021 · I build a facial recognition software in python, and I want to send x and y cords of my face to my arduino uno through the Serial port (COM3 in my case) Feb 29, 2024 · COM port is not in use. Feb 25, 2020 · 2 Since you tagged this asp. New comments cannot be posted and votes cannot be cast. 🔌 Faulty USB Ports: Sometimes, the problem may not lie with the USB drive itself but with your USB port, which will also cause you to be unable to access the USB drive. System recognizes the cable, but when I try to run the application to access the peripheral, I get the message "Serial port COMx is in use" (x is whatever port number is assigned by Windows or by me). Dec 6, 2023 · Learn how to create and manage virtual (USB) COM ports on Windows 11 Home (Surface). Nov 10, 2013 · A port stays open all the time, so be sure to close ports that you don't need open anymore. Oct 4, 2018 · 8 I use windows 10 so I try to kill the port this command netstat -ano | findstr :8006 taskkill /PID 3984 /F but I didn't kill the process. The COM port is usually COM3 and is set at 38400 BAUD through Device manager. Mar 11, 2025 · I'm running SW on a Windows 11 laptop that can not connect to an RS-232 dongle reading ASCII text GPS data at 38400 BAUD rate. Can… Jan 15, 2025 · To resolve USB stick access denied in Windows 11, use a systematic troubleshooting technique. Have spent half a day trying to overcome "access is denied". I reboot, open the port (arduino ide) works ok, then, some OTHER application is stealing the port and after a while only way to access the port is new reboot. Jan 17, 2024 · Hello, USB Storage device is inaccessible in Windows 11 device. The "drive is not accessible, access is denied Windows 11" message implies that your Windows 11 PC has restricted the external hard drive, causing the "Access denied" pop-up while browsing your system. Adapters with older Prolific chipsets are not compatible with Windows 11, but newer ones should work. Dec 24, 2025 · Windows 11 manages COM ports through Device Manager, where hardware settings can be configured and troubleshooting can be performed. Nov 9, 2023 · Hello I encounter some problems under Windows 11 23H2 to access a simple Serial Port under . I have reinstalled the driver many times using Device Manager, followed many online help for COM port issues in Windows 11 including power settings. Restart (several times) Changed port name (tried port 2, port 11, port 15, ) Restarted after ever time Checked windows firewall and allowed serial. ', None, 5) If 6 days ago · 💽 Malware or Viruses: When your drive is infected, access denied on USB may appear. After connecting the device to my laptop it also shows up in the device manager but it seems that I'm unable to open the COM port for communication. Feb 24, 2023 · I am having a problem with using a simple serial port trigger in psychopy sending simple triggers to an Arduino board. I need to have a small delay (500 ms works) before being allowed to open the port successfully Restarting windows after it was shut down with shutdown /s /f /t 0 is the only reliable solution to open up the port again. For this I use a CH340 RS232 to USB cable to connect the device with my laptop. serialutil. The activation process does not have sufficient permissions to modify the licensing store or communicate with the activation service. 11 and installed v2. net, are you trying to access the port with multiple threads? (as in on a request, accessing the port, creating the connection, sending data, closing connection, closing the port? If you are, this is also a problem. But it comes ERROR: The process with PID 3984 could not be terminated. This post shares 6 solutions to fix this problem. If I am not mistaken, only one thread can access a com port at a time. 6 days ago · 💽 Malware or Viruses: When your drive is infected, access denied on USB may appear. Close () code in your catch block to free that port. 11 or a windows update changed the FTDI driver to a new one that would not work with my old FTDI board. However I received the same results. After I restart normally (due to windows updates or similar) the issue comes up again an I need to shut down windows with that command. You may also need to elevate your credentials depending on the account you are using and User Access Control settings. COM port from adapter no longer works after upgrading to Windows 11 If you have an RS232-to-USB adapter with a Prolific chipset that stopped working after upgrading to Windows 11, you will likely need to buy a new one. Does Windows 11 handle COM ports differently than Windows 10? Win 11 COM port Advanced Settings has more options than the Win 10 one, making me think there might be a difference in how the Windows versions handle COM ports. I also tried using PuTTY to communicate, but it also didn't work. I am trying to upload any sketch to Nano and port access is denied. Here is what I've tried so far. Did you recently install updates on your print server? If so, which patches were installed? May 20, 2019 · RE: Firmware update issue: avrdude has no access to COM port Also please make sure that there is no other application accessing your serial port, for example Cura or Pronterface. Chirp could not open port 'COM 4': PermissionError (13, 'Access is denied. Oct 11, 2021 · Windows cannot connect to the printer. However, there are no USB restrictions, and the proper drivers have been installed. All drivers loaded. Restarting my computer fixes the problem and frees up the port but eventually the problem always comes back. Reason: Access is denied. \\COM3": Access denied. The problem is that the COM port does not show up in the drone's software. ’, None, 5). COM5 is in the ports list and I am the administrator of my desktop, so what gives? How to determine what is using serial port resources causing access denied? Ask Question Asked 9 years, 2 months ago Modified 3 years, 6 months ago Jul 14, 2025 · This comprehensive guide is your definitive resource for understanding, troubleshooting, and ultimately eliminating “Access Denied” errors in Windows 11. Radio is On. NET in C#. Jan 15, 2025 · To resolve USB stick access denied in Windows 11, use a systematic troubleshooting technique. Cable uses a CH340 chipset, which both versions of Windows seem to recognize without a problem. Feb 26, 2025 · Hello Everyone, I am facing a COM port issue when connecting an FTDI/RS232 device via MobaXterm and Putty. In all cases windows Device Manager showed the com port and running properly. Somehow either the installation of 2. Jul 2, 2023 · I uninstalled v2. Open Windows Firewall by swiping in from the right edge of the screen, tapping Search (or if you're using a mouse, pointing to the upper-right corner of the screen, moving the mouse pointer down, and then clicking Search), entering firewall in the search Explore AweSun Remote, the all-in-one remote desktop software designed for seamless remote control, remote access, and secure remote desktop experiences. My laptop is up to date as far as patches are concerned. Apr 12, 2022 · Bought first Arduino kit today. When we use the CC processor to initialize the device, if fails, saying Device cannot be initialized. Does Windows have a BUILT-IN way to "make sure" or do I have to look for a 3rd party tool? Jan 18, 2025 · If you need to constantly access the files, use the hidden Administrator account to make the necessary changes to your system and fix the ownership or access issue. If the printer is connected to a router by ethernet, you won't have to first authenticate, unless security has been set up on the printer. This article provides step-by-step instructions and troubleshooting tips for setting up virtual COM ports for improved device connectivity. How on Earth I can identify what app is stealing my com ports? Mar 8, 2025 · Windows 11, like its predecessors, supports COM ports, but many users may not know how to enable or configure them effectively. 0 Port on computer Plug into USB 2. I did install: Windows 11 Version 22H2 for x64-based Systems (KB5027303) a few days ago and it might be the culprit. 2020 Programming Table of Contents [hide] 1 How do I fix COM Port Access Denied? 2 How do I release COM ports in Windows 10? 3 How do I fix COM ports? 4 How do I clear all COM ports? 5 How do I know if my USB to serial converter is working? 6 Can you open COM4 with serial port 1? Overview on access denied error If you are getting Access Denied error in Windows, then you are not alone. Apr 27, 2019 · The device plugs in to a USB port, which is set up to be a virtual COM port. Supporting Windows Remote Desktop (including Win10, Windows 11, and Win7 remote desktop), Mac remote desktop, Ubuntu & Linux remote desktop, it also integrates Web Remote Desktop, VNC Remote Apr 15, 2024 · 0 I bought a laptop with Windows 11 Home, which I intend to use with my drone. By Mauro Huculak (@Pureinfotech) , Windows How-To Expert and IT Specialist with 22 years of experience. running Chirp as admin. Below is the message How can I find where this is blocked by Intune Policy or Windows Group Policy? Please help Jul 17, 2025 · Regain access to restricted files and folders in Windows 11 by adjusting permissions, taking ownership, and troubleshooting account issues. When I look at their log files, there a message that says “Access to COM 2 is Denied”. This happens no matter what port number I set my Arduino to in the Device Manager (and of course in the I had to make changes to an UNO project, and every time I go to upload the sketch, I get a COM error: "\\. Aug 9, 2019 · The UNO powers up, is recognized on the com port, and returns the board info when requested from under the "tools" heading. Does Windows have a BUILT-IN way to "make sure" or do I have to look for a 3rd party tool? Mar 24, 2024 · COM ports not visible in win11 device manager, so Arduino not showing "Port" in tools menu. Follow this guide to fix it fast. Did this help you? What other tricks do you have when uploading a sketch fails? Nov 28, 2011 · It is not opened when port is None and a successive call to open () is required. I need to have a small delay (500 ms works) before being allowed to open the port successfully Apr 15, 2024 · 0 I bought a laptop with Windows 11 Home, which I intend to use with my drone. Oct 28, 2021 · 5 My Windows 10 computer keeps getting stuck in a state where many ports are unable to be used, but when I try to find and kill whatever is using the port I can't find anything. Normally I can change the com port number to anything, and set the fleet software to read the GPS on that com port. Sep 30, 2012 · I get the following error message Access to the port 'COM5' is denied. SerialException: could not open port 'COM4': WindowsError(5, 'Access is denied. x - Arduino Forum Jan 1, 2016 · I am trying to use my Arduino UNO on my Windows 10, but unfortunately I get an "Access to COM Port is denied" error I already tried to change my COM Port number (only my Arduino is using a COM Port), but nothing changes. Feb 13, 2023 · Hi All, Old problem, no solution. USB Detected But Not Showing up - Windows 7/8/10/11 | VTeach24 How to protect excel sheet with password | password on excel sheet| VTeach24 Dec 17, 2022 · "Permission Denied" can happen if some other application already has the port open. 05. Dec 28, 2023 · I tried to use a serial port monitor software to troubleshoot but that application also claims it cannot open the port, so my inclination is something is securing all these ports. 3: If any exception (Access is denied) occurs, write the Port. To find a specific issue, use the search function on your browser (CTRL + F for Microsoft Edge). 4: Make object of Serial port before try catch block to make it universal. Check that you don't have a terminal program open on the same port, etc. 05) 4) I reboot computer, the problem is gone, but it happens again after a while 5 6 days ago · How to fix Samsung PC drive C is not accessible (access denied) on Windows 11 A Samsung app conflict is breaking Windows 11 access, locking users out of the C drive after recent updates. This article will guide you through the steps of enabling a COM port in Windows 11, detailing the process, troubleshooting common issues, and offering helpful tips. Have googled and tried everything I have found sof far : List of things I have tried : Changed Port Number Use Netstat to identify ports in use : Select “Unused” Port Restart Arduino Restart Computer Use Different Cables Plug into USB 3. Jan 18, 2026 · Conclusion "Access to COM port denied" in C# is rarely mysterious once you methodically check for port conflicts, permissions, cleanup, and hardware issues. Do you have any ideas as to what is causing the… Dec 24, 2025 · Windows 11 manages COM ports through Device Manager, where hardware settings can be configured and troubleshooting can be performed. I have tried entering the right baud rate of 9600 from the port setting of my device manager. Jan 23, 2025 · I have the same issue with a slightly different message (Access denied instead of 0x1B1). Start with verifying the port name and checking for conflicting processes, then move to permissions and cleanup. Feb 16, 2021 · You could try close other software that may be using the port in the Task manager, and try again. /dev/ttyUSB0 on GNU/Linux or COM3 on Windows. The program keeps giving me an access denied error - PermissionError (13, ‘Access is denied. Feb 9, 2024 · I'm trying to use my laptop with Windows 11 to communicate with a device over my laptops COM port. Sep 20, 2021 · How do I fix COM Port Access Denied? Jacob Wilson 15. Here in this video tutorial, I will show you guys how to solve the access is denied error problems on your Windows 11 PC or Laptop. The drone's flight controller connects to the laptop via USB and presents as a COM port in the drone's software (Mission Planner). Mar 9, 2011 · After that, it is best to uninstall the printer, browse to the first computer in Windows Explorer by entering in the address as \computername\, and then right-clicking on the printer, and choosing Connect. Was working just a few days ago, now not so much. The process involves verifying hardware presence, updating drivers, and configuring port settings to match device specifications. 0 Hub Verified Port in Sep 13, 2024 · Using the above 9 ways, you can quickly solve the problem of USB drive access is denied on Windows 10 or 11. Mar 8, 2025 · Windows 11, like its predecessors, supports COM ports, but many users may not know how to enable or configure them effectively. \\COM2": Access is denied. Nov 28, 2011 · It is not opened when port is None and a successive call to open () is required. poof! access denied errors are gone! Dec 17, 2018 · Hello, When I connect MxChip board to Windows 10 PC via USB and try to execute "IoT Device Workbench:Configure Device Settings", following message is shown in terminal. The controller was working fine, but I am not sure if the problem started after a series of Windows updates. Please use your own thread, COM3: Access is denied - IDE 1. Serial( "COM4", 9600, timeout=0. . Usb Port Access is Denied in windows 11/10//8. avrdude: ser_open(): can't open device "\\. ', None, 5) If Feb 8, 2011 · I'm also having this problem but i can't find the device manager anywhere. Ensure seamless device communication by following these simple instructions. on my windows 10 machine. We’ll walk you through proven methods, from straightforward graphical solutions to powerful command-line tools, ensuring you regain full mastery over your digital workspace. You can also get useful information to recover data from your USB drive. \COM5": Access is denied. Tried with 2 different FTDI cables, multiple USB ports. May 27, 2022 · I do not have an advanced tab on the properties window to change com port address in Windows 11. e. While working on my own serial port application, I found out that if I try to open the serial port just when the connection event is triggered, the port cannot get opened. Anyone else have an issue? John Mar 16, 2026 · What it means: Access denied. Archived post. This sounds like its related to the PrintNightmare mitigations discussed at length for months on Reddit. Dec 18, 2025 · Struggling with external hard drive access denied Windows 11? Discover easy fixes, ownership tips, and data-safe solutions to regain full control. Find information on recently resolved issues for Windows 11, version 25H2. ') Here are what I did: 1) I check device manager, COM 4 can be seen, but cannot open 2) In my code, I do close COM port after using it 3) Here is COM config in my code: ser = serial. Your port might be busy or you might need administrator access, try running it with administrator access. ',None, 5) getting above message when attempting to download from UV5r. Jun 10, 2022 · Whenever I install the MicroPython to my Raspberry Pi Pico, Thonny returns this message: Unable to connect to COM5: could not open port 'COM5': PermissionError(13, 'Access is denied. In the Advanced Settings window select a new COM Port Number: Click OK and close all Device Manager windows. I just cant get win 10 to let me use the com port to upload a program. this is driving me nuts. Windows may ask you to restart your computer, but in my experience the Arduino IDE is quite smart to detect port changes immediately. Please kindly refer to this detailed instruction: How to use Windows 10 Task Manager to kill processes that drain resources Access Denied Error generally occurs when you do not have the required permissions to access a file or folder. May 16, 2024 · To fix the windows 11 printer access denied problem, hop on this article to find out the best troubleshooting solutions available. Feb 12, 2026 · Provides troubleshooting for the issue that shared folders can't be accessed from File Explorer in Windows 10. This is a quite common problem related to permission, file system, etc. May 15, 2014 · This exception can occur when some other program is accessing the COM1 port. Other USB Devices are working (like pen drive, portable disk). My earlier installations with Windows 10 and Oct 11, 2025 · Encountering the “Access Denied” error on Windows 11 can be frustrating, especially when you’re trying to access files, folders, or programs vital to your work or personal use. 1/7 How to Enable or Disable USB Ports In Windows 10/8/7 [Tutorial] How To Disable USB Drives on Windows 10 Tutorial Fix USB Flash Drive Does Not The serial port shows up in Windows 10 device manager as USB Com Port X, where X is the port number. 10. Jul 20, 2025 · Have you ever encountered the dreaded “You have been denied permission to access this folder” message in Windows 11? It’s a frustrating roadblock that can prevent you from accessing critical files, especially after connecting an external drive or restoring data. Windows OS? If so, verify in device manager what com port is being assigned. UPDATE: I moved the COM port Open/Close out of this code and open the port when the app starts and close when the app closes. Are you receiving an "Access Permission Denied" error in Windows 11? Here's how to resolve it. fazkst ngulw tqica baz glrg eguk ozmajdj jdpoh sqkbr jubqa
