I noticed the same thing when using hammer optimization in 22.1

Hmmm…I have no problems (apart from the MalWareBytes issue I reported separately), and if the Undo change fixed things it implies that the problem lies in your hard drive. The acid test would be to reinstall the previous version and see if the problem is still there or not.

Dear colleagues,

For us, the undo files were slow already over 5 years ago. This was for a large part because our company has the user profiles stored on the network. This means basically that the undo-files also were stored on the network and although our network is quite fast, this still resulted in slow behavior of Zemax. Still saving files takes far too long… however, the undo-files location is a user setting and we set this one to a local folder on the hard drive. This for us solved the slow interface due to the undo files. Setting it to “memory” did also work, but the one cannot go much in the past, which for me is no solution at all. Maybe a setting “memory, multi step” would work…

Regards,

Rob