Solved! Go to Solution.
I had the same problem with Secure Folder version 1.8.01.5. Using the Google Play Store, I was able to look up Secure Folder and uninstall all updates to the app (can't completely uninstall because it is a system app). After uninstalling updates, I was reverted to version 1.8.00.41, and Secure Folder now works! No more app crashing. Interestingly, after reverting to 1.8.00.41, searching the Google Play Store, Galaxy Store, and "About" section in the Secure Folder app all show 1.8.00.41 as being up-to-date/ the current version! My guess is that 1.8.01.5 was broken and caused these crashes, so they pulled the update, but failed to roll back that update for anyone who already updated. At least it's working now.
I'm not really sure where/how files within Secure Folder are stored.
It seems to be related to G991U1UES5DWA4 which may have contained Secure Folder 1.8.01.5.
Having the same issue, I use my fingerprint and it opens for a split second and crashes immediately. Tried clearing the cache and that didn't work. I can't even disable secure folder, it's grayed out and I can't do anything. I'm able to access some apps in the folder since I get notifications but I can't access the rest of the folder still.