Soooo, I screwed up. I have 3500 images in my catalogue. I did all sorts of cropping and metadata etc to them. Then I used a plugin to batch change the dates. Because the plugin works "behind Lightroom's back", i had to go Metadata --> Read metadata from files. However, because I hadn't saved the metadata & changes to the file, when it finished, all my crops & metadata were gone. CRAP! Now, if I go to develop module and chekc out the history, the last thing done on all 3500 pictures is "reset settings". Is there a way to delete the "reset settings" command to all 3500 images at once? Doing that command 3500 makes me want to cry.
I'm not sure if 'Read Metadata' can be undone by the 'Edit - Undo xxxx' menu. Otherwise, your best (only?) option is to replace the catalog by a backup copy.
"I'm not sure if 'Read Metadata' can be undone by the 'Edit - Undo xxxx' menu"
There is an old plugin, ScrewAutoSync, which could remove the top history steps on a batch of photos:
It's author passed away years ago, and I haven't seen any reports if it still works in newer versions of LR. If you try it, or anything else, be sure to make a backup of your catalog, and test that backup to make sure you can restore it!
"I used a plugin to batch change the dates."
It's so frustrating that Adobe has refused to provide an enhanced Edit Capture Time command, and it has also refused to provide the simple enhancement to its SDK for plugins to allow them to easily change capture dates.