While I wait for a new internal HD cable for my 13' MacBook Pro (2012 model) I've been running the main SSD (which was the internal drive) connecting externally via USB-SATA adapter. That was working fine for several days, but today it starting getting glitchy - files that I deleted wouldn't be deleted after the computer went to sleep and came back, for instance. Now I have the Blue Screen Of Death on start-up. Any reason the ability to function from the main drive working externally would degrade over time, and is there anything I can do about in the short term?
Update - just don't try to run off your main HD externally like I did. New HD cable came and replacement worked great, but the SSD must have lost power in the middle of something important because it was scrambled, had to wipe it and start over from a Time Machine back-up. No major harm done, but I should have been more careful.