>>What I find interesting is that with a short delay or none, I sometimes get several dropouts in a row. So my guess is that there's some windows service that occasionally blocks the access to the clipboard for a very short period.
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>You could experiment with disabling your antivirus' real-time scanning component.
>
>You might be able to work around the issue by using Win32 API calls. I haven't done that myself but Googling [clipboard access windows api] brings up some promising-looking results.

As long as a short delay resolves my problem, I won't spend any more time on this issue.