[popcornmix]

Looks like maybe a general bug
Win 5.95.5 same issue, only much faster. Where the Pi2 takes >5min, the PC does it in less than a minute.
When updating on startup, it goes through the database twice. The first time in about a minute, then immediately after, faster, in about 20 seconds, then hangs on the same folder for 20 seconds before completing.

I think a report in the OS independent forum may be more likely to get a response from someone who knows the answer.