Copy-paste stops working on Windows 7

A bit late, but hopefully this can still help someone.

I have this exact same problem as well, on Windows 7 64-bit too. For me, I just found out it was caused by Outlook 2007.

You can find out which application is keeping a lock on the clipboard by running David Candy's app: http://windowsxp.mvps.org/temp/GetOpenClipboardWindow.zip

This gives you the PID which has the lock.

Got another solution from the Microsoft Forum Thread

The solution worked for me is

Go to Start (Start/Run); Type the following in the search box: cmd /c “echo off | clip” then hit Enter.

Piggie-backing on what SSilk said in his answer, try to turn off Notepad++ if it's open. In my case too, it was interfering with the clipboard on a Windows Server 2012 R2 machine.

Worked great for me. Turns out Notepad++ had the clipboard locked. Possibly because I tried to copy a huge amount of data into it a few minutes ago (300+MB). If the clipboard is locked, it will give you the PID of the locking process. If you can't find that in normal task manager, as per the program's suggestion, open System Information (Start->Run->msinfo32), that has a more complete list of running tasks. It pointed me to Notepad++ and when I went there, NPP was behaving a little strangely (couldn't type in all open files, etc). I closed it and the clipboard freed up. – SSilk Mar 30 at 16:29

If you have Skype installed, then you will have to disable keyboard shortcuts in Skype. To do that, open Skype > Tools > Options > Advanced > Disable Keyboard shortcuts or Just Disable Ignore call Option as it uses the key bind "Control + C" which conflicts with Windows' copy to clipboard.

I had this problem on a remote desktop connection. Even after trying @Ludovic's solution (Copy-paste stops working on Windows 7) it did not go away.

What worked for me was opening task manager and killing a process called RDP Clipboard manager