In short: using the November update of Power BI, the options menu in Power BI Desktop got stuck, forcing me to kill the process as a last resort.
I just lost a lot of time, due to the options menu not applying my requested change (disabled auto date/time tables in an existing report). The options menu itself seemed to work as intended, I could change tabs, change options, drag it around and toggle full-screen / window mode, but it refused to apply anything when clicking the "ok" button and what's more, it also refused to cancel / close itself.
Effectively this forced me after a while to forcefully kill Power BI in it's entirety, resulting in loss of work, since after "restoring the report", I ended up with a corrupt sort of file. I got a couple of strange messages when opening the restored version (the yellow bar at first showing at the bottom of the program, half visible and half hidden behind the statusbar): my calculation groups needed refreshing (which had never changed), my changes were not applied (this is true, though I never intended to apply any changes in the M queries), it said tables were missing data (?) and refreshing (which started automatically) failed with some obscure error I have never seen before which I didn't write down, but said something like I couldn't create a certain column, since one already existed?
We have seen on the internal platform that other engineers have reported this issue and submitted it. The engineers on the product team are now aware and will do their best to resolve the issue. I will update here if there is any progress, so please be patient.