Can not open existing catalog after latest lightroom update

After updating lightroom classic to the latest version, when I open an existing catalog on an external drive, it forces me to upgrade this catalog.  After that is done, I am not able to open the newly upgraded catalog.  It will just hang there for 10-15min.  The catalog has about 1tb of images and the drive is fairly new and rarely used.  I have tried it 3 times already with the same result.  Panicking here that I will be losing my previous work.