I have exactly this problem (2022-02-02). I get the option to override or save as new lot, but neither option works. Did you solve it?
Troubleshooting I've done so far: removed/disabled mods, tried repairing the game and removed cache files. Saving lots to my private gallery worked fine until yesterday.
(CM: Multiple posts merged. Check out this post for tips on how to edit and add more to a post.)
@princess_JM_666I can confirm this. It was working again for a while as it should but now the issue is back. I mainly have this issue with downloaded lots from the gallery. Example: I download a lot from the Gallery (mainly lots created by Schnuck) and replace an existing lot in game. I do my changes, rename the lot to its original name. I reupload it to my private Library. I do changes again like rearranging and replacing furniture and so forth. I save and reupload again. Game will ask if I want to override the already existing SAVED lot. I click yes. I exit the game. Later I log back in and visit the new lot. I do so more changes and save/reupload again. Game forgets that the lot is already uploaded and saves it up as a new uploaded lot without overriding. I have to delete the already saved-up lot to prevent doubles.
