Clipboard used by another application

The message indicates that another application is holding the Windows Clipboard open so Excel cannot complete the copy or paste operation.

Use these steps to work around and reduce the issue:

1. Close other applications that might use the Clipboard
   • Common culprits include: other Office apps (Word, Outlook, PowerPoint), web browsers, screen capture tools, remote desktop/virtualization clients, and clipboard managers.
   • After closing them, try the copy/paste again in Excel.
2. Add error handling if using VBA macros
   • If a VBA macro is doing the copy/paste, wrap the copy/paste code in an error trap that lets the user retry after a short pause when the Clipboard is busy. For example, handle the “Can’t open Clipboard (Error 521)” or “Can’t empty Clipboard (Error 520)” conditions by showing a message box with Retry and Cancel and pausing briefly before retrying.
3. Avoid rapid repeated clipboard operations in macros
   • Many individual copy/paste operations in a loop can increase the chance of hitting clipboard contention and can slow Excel down.
   • Where possible, reduce the number of copy/paste calls (for example, copy ranges in larger blocks instead of cell-by-cell).
4. Consider disabling Active Clipboard for heavy macro scenarios (advanced)
   • For scenarios where a macro performs many copy/paste operations and performance is poor, Active Clipboard can be disabled via the registry after installing the relevant hotfix. This is an advanced step and affects Office-wide clipboard behavior:
     1. Back up the registry first.
     2. Run regedit.
     3. Go to: HKEY_CURRENT_USER\Software\Microsoft\Office\xx.0\Common\General (replace xx.0 with the Excel version: 16.0 = Excel 2016, 15.0 = Excel 2013, 14.0 = Excel 2010).
     4. Create a new DWORD value named AcbControl.
     5. Set its value to decimal 2147483648 (hex 80000000).
     6. Exit Registry Editor.
   • After disabling Active Clipboard, Office features that rely on the Office Clipboard (such as storing multiple items) will no longer be available.

If the problem persists even with other applications closed, restart Windows to clear any process that may be holding the Clipboard.

References:

• Clipboard
• Can't open Clipboard (Error 521)
• Can't empty Clipboard (Error 520)
• Macro takes longer than expected to execute many individual copy and paste operations in Excel 2010 and later