OK, I hate to mention the annoying troubleshooting but it sounds like it could be a memory issue. You said that the issue happened some days ago. Have you tried rebooting to see if your computer's resources are preventing the copying. (This can occur from your browser or other things) and if you have maybe the data that you are trying to paste is too much for Excel to handle. I had this happen with one range I was copying that was over 12000 rows by 50 columns. so I just copied and pasted half the data then the other half. Let me know if a reboot is not the issue. We will get this figured out.