Should I expect restoring Yosemite from a Time Machine backup to take forever? El Capitan was a disaster for Office Mac 2011, specifically Outlook. The recent Microsoft update resolved the problem with Outlook crashing, but it didn't fix the problem I had where email sent to me was disappearing into the ether.

After conversations with both Apple and Microsoft support, neither who had a resolution, the final advice was to restore to the previous OSX, Yosemite. I used Command +R to restore from a Time Machine image and after 6 hours with the startup bar stuck halfway, I stopped it and came back in to check the disk and it's OK. So I started the restore again, and it back at the same halfway point and has been there for 6 hours and counting. Should I ride it out? How long should this take? I'm running on a 2014 MacBook Pro. Any reassurance or advice is appreciated!
First things first, make sure you backup before all of this:

When you restore from a backup you are not restoring to a previous version of OS X, you'll need to backup, erase the disk, reinstall with Yosemite and apply your backup. If you need help with this please comment this answer, I'll give all the detail needed 

Tiferrei