I recently copied my Lightroom (LR) catalog onto an external hard drive. I then connected the ext HDD to my Macbook Pro laptop, opened LR, and opened that catalog.
Now I see an exclamation mark in the upper right corner of the photo icons that looks like this:
I don't understand what is going on, and I don't want to overwrite something that could end up being a previous edit. Can someone explain this to me?