I have had problems with activating the Clipboard History Switcher.
And it seems to be because Microsoft Office 2011 creates images of the clipboard content, which is very large.
See this forum post:
@gglick made a macro, which solved it in Excel. Thanks.
I have modified the macro to also cover Word and PowerPoint.
And made so the clipboard gets clean of images when the Office programs deactivate.
Keyboard Maestro 8.0.4 “Auto-Filter Clipboard Office applications deactivates” Macro
Keyboard Maestro 8.0.4 “Auto-Filter Clipboard Office applications clipboard changes” Macro