Windows 11 shows error 5 when trying to start a putty serial connection. Access denied. Previously worked, never a problem until now.

Question

Windows 11 updated to latest

Putty updated to latest

Teraterm installed and the same exact problem

Two different sets of previously good serial cables tried

Drivers updated cor serial devices and said to be current

Different USB ports on laptop tried, with different COM ports tried

I can log in using same cables with Fedora Linux no problem

This appears to be something where maybe a Windows update changed something

I have been using this laptop and these cables and putty for years and up to now have never seen this

Answer 1

Hello,

For the issue you encountered with error 5 (Access Denied) when starting a serial connection using PuTTY on Windows 11, here are some possible solutions and analyses:

1. Run PuTTY as an administrator, which will grant PuTTY higher privileges and may help resolve the access denied problem.
2. Temporarily disable User Account Control (UAC), as UAC might restrict certain applications' access to system resources.
3. If the problem occurred after a recent Windows update, you can consider rolling back to the previous version before the update.
4. Try using other serial communication software (such as SecureCRT, MobaXterm, etc.) to see if a successful connection can be established. This will help determine if the issue is specific to PuTTY.

I hope the information above is helpful.

Best regards

Zunhui

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