This seems to have happening all the time.
I have the latest version of the app (1.5.5) installed on my Windows 11 laptop (Lenovo Thinkpad X1 Extreme Gen 2 with 16Gb RAM).
My photo collection is on a 3Tb external drive connected via USB3 port. The photo collection is around 2Tb in size (going as far back as year 2000).
I installed the app a few days ago and the the app is still scanning my folders but wheneve I leave the app running in the background while I use my laptop, each time I went back to the app to see the progress it won’t be freezing. Clicking inside the app window doesn’t do anything. Moving the mouse over the menu bar at the top or the status bar at the bottom of the app windows, the mouse cursor changes to spinning wheel. The status bar shows the last known image being scanned and it just seem to stuck there at some random image.
Most of my photos are JPGs and more recent some are DNGs, and some MP4s, but it seems to hang at some random place, and not at particular file type.