Maintenance for the week of August 3:
• PC/Mac: No maintenance – August 3
• ESO Store and Account System for maintenance – August 4, 5:00AM EDT (9:00 UTC) - 4:00PM EDT (20:00 UTC)
The initial log-in after a patch is always a lengthy one. It has been like this, with a heads-up from Gina prior to it happening, since the Greymoor update.
The game has to re-populate the database with all of your character data. So, side-note, the more characters you have, the longer it will take.