Backspace Polygonal Lasso

Sorry to hear that it didn't help. Have you considered rolling back to an earlier version? If undo was working correctly for you previously, that is probably the best solution while on a deadline. When you have more time, try updating again. Other solutions include using the Creative Cloud Cleaner tool (https://helpx.adobe.com/creative-cloud/kb/cc-cleaner-tool-installation-problems.html). 

I followed the instructions, removed the preferences, back to default settings and this did not work. I'm at a loss and on a deadline. So frustrating

I'm using windows 11, but I will check out the link you sent. Thank you!

Hi @RileyVPhotography, pressing the Backspace key on Windows 10 works for me to undo the last click with Photoshop 26.1.0 Release. I can make a video to show you that it works if needed. Have you tried manually resetting your preferences? That often clears things out. Let us know how it goes! https://helpx.adobe.com/photoshop/using/preferences.html#Manually

Sorry, I couldn't figure out how to edit original post. To Update the original post. I have 2 versions, 26.1 and 25.12. I cannot "Undo Click" for the polygonal lasso tool in either version.