We could not copy the content to the Clipboard, it is in use by another application. You can still paste your content within this workbook but it will not be available in other applications.

From what I can tell the excel clipboard function does not mitigate well with the Windows OS clipboard and CPU. Good luck on trying a dependable, online workaround for Office 365 Excel (it seems every MS coding and/or feature "improvement" is an overall digital ecosystem detriment ... I guess it keeps their programmers employed).

WORKAROUND: I sometimes have to open the Task Manager to determine what apps are using a lot of the CPU and close that. In conjuction with that I often try to clear the the Excel Clipboard function located on the left of the ribbon and expanding it with the lower right down arrow then clicking the Clear All button to remove all the copy/paste conditions that are listed.

It may help to automate the Windows Clipboard cmd with the Clear Clipboard command icon. See: How To Create Clear Clipboard Shortcut In Windows 10 - YouTube

Also clear your RAM which can be done conveniently with the freeware/shareware Advance SystemCare RAM monitor/clearing function. While in the Task Manager, you can also remove unecessary apps from the Windows startup by going to Task Manager-> Startup list. Sometimes these lingering unecessary apps may interfere with efficient memory activity.

Not that these solves the problem --- it is just that --- a possible workaround.

I totally agree with BSM#48. It happens to me every time I open Excel. I get that stupid message. Click off of it, and then the clipboard works.

It seems that Microsoft is more concerned with inventing "features" with no useful purpose, than in fixing it's screwups.

Same issue here. Reboot is the only thing that fixes this. Something happens after the PC goes to sleep and wakes up. I'm on Windows 11 and after my PC has gone to sleep and woken up I start getting these weird clipboard/copy & paste issues intermittently. It never happens if the PC doesn't first go to sleep. The excel error is the latest of these and I suspect whatever is the root if this is at the root of the copy & paste, in general, just not working. That also includes sometimes even the ability to click the shutdown or reset icons on my PC. Not only that, Windows 11 hijacks your normal force shutdown by making you slide a window down to shutdown the PC if you hold the power button. If that freezes, and you are on a laptop, better have a pin handy.... I'm so frustrated by this, and frustrated that Microsoft is trying to be Apple. Have your own identity Microsoft, there as a reason I didn't go Apple.

Thank you KA, this solution worked for me! I was struggling from past 2 days so much appreciated

The problem, for the most part, has stopped. Not sure what could have fixed it. I do ocassionally get a different warning where it suggest I have a copy function selected already and pending. It then prevents me from selecting cells. I have found that saving the Excel document and restarting reset its normal function.

As for enabling Live Preview, here is a link with the procedure:

How to Enable Live Preview - ExcelNotes