Why Does Windows 10/11 Copy and Paste Stop Working After A While?

But when mine goes out, Notepad and any others don't copy/paste, either, so it's not just an Office problem.

Your welcome Art. I have over 45 years in IT, mostly Mainframe problem solving for a very large automotive company, very high-pressure job so I have some knowledge on the information they might need to fix the issue. I'm willing to give them the time and information they might need. I think my Level 3 person has now engaged engineering because they make changes to my P/C remotely and let me test for a few days. I have been giving them as much time as possible, sometimes having two - three calls a week. I'll keep this site up to date with their findings.

Not sure it's all that helpful but here are some observations:

• The paste function is typically not working when I return to my computer after a few hours or more "away". It doesn't appear to matter whether I lock the computer or not. I think if I hibernate the computer it avoids the problem but need to test further to be sure. My "fix" is to "Restart" as it's relatively quick and always works.
• "Copy" does seem to work or at least I see copied content land in the clipboard stack.
• Some other things that tell me I have to restart.
  • The task manager can't be started from the task bar. Right mouse click on the task bar shows the menu but "Task Manager" won't highlight to be selected.
  • The computer also cannot be restarted from "Windows Start" menu with the mouse. Like the task bar behavior above I can mouse click on "Start->Power" but cannot highlight and select "Restart" (nor "Hibernate" or "Shut down" for that matter). I can however use the keyboard sequence "Win+X -> u -> r" to restart the computer (my "go to" solution)
  • Outlook classic will not let me open certain e-mails and calendar entries with a message "this item is not available right now".
  • If I go to Excel and try to cut and paste in a spreadsheet Excel will report that "The clipboard is currently in use by another program".

These other observations led me to believe it's a memory problem but I have upgraded my computer's memory and task manager (when I can get it started) doesn't indicate a memory saturation. I also changed from using Edge that is typically showing high memory usage to Brave and while Brave is noticeably faster and "lighter" it didn't change the copy/paste behavior. Note that not all these symptoms are manifest every time.

I hope this is useful, any feedback highly appreciated.

No update, still working with Level 3 support and now engineering. I'm having the same issues when waking up the P/C from sleep mode, copy and paste fails. I will forward your response to Level 3. What I'm finding is that when I talk to support it's like I'm the only person having the issue. We need more users to contact Microsoft Support and request their problem be escalated to Level 3. It took me several calls and over 2 months to get to Level 3. I'm willing to work with them to get the information needed to fix this issue.

In our case, the copy (clipboard) issue is specifically related to a custom WPF app, and may be related to a Visual Studio update in conjunction with the 23H2 build. Further, it is only happening randomly and for a small subset of the population. Maddening and we've done a wide array of troubleshooting tasks, even replacing mice/keyboard combos. The TeraCopy test did not offer a resolution, uninstalling and reinstalling the custom app did not offer a resolution, and reviewing Task Manager during a copy operation provided no clues as to other conflicts or processes involved.