DaveB_CT I've had Slack get the spinning beach ball as well, but at first I did not associate that with RDC because I wasn't pasting into Slack. This condition in every other application is triggered by trying to paste from the clipboard. I now think Slack is a victim of this RDC bug. I suspect the problem is still only clipboard related, so it makes me wonder what Slack is doing with the clipboard. Does it retrieve the contents every time it's brought to the foreground? Apparently it does; I just found https://apple.stackexchange.com/questions/464134/slack-silently-copying-clipboard#:~:text=What%20do%20the%20Slack%20developers%20have%20to%20say%20about%20this%3F&text=The%20odd%20thing%20is%20not,paste…%20then%20doesn%27t. which offers a way (from Slack support) to disable this behavior.
Using Mac OS X 12.6.8 and Remote Desktop 10.9.2. Beginning two versions back (10.9.0?), copy and paste works for a while after launching RD, but it eventually fails when copying from the remote mach...