I've been using Google's AutoBackup feature for photos for a while. It is quite nice - if you upload photos no larger than
2048x2048 the storage space is free, and you get an easy, fast (Google servers) way to access your photos from anywhere using any device.
Recently, the auto backup feature on my Android phone has stopped working. All I was seeing was a stuck progress bar saying something like "Backing up N photos...", but nothing was happening - it was completely stuck. My phone was charged and connected to WiFi so everything was supposed to work.
I tried clearing caches, data, reinstalls and whatnot. No luck. Fortunately, after scouring buried forum posts, I found the problem. I'm posting the solution here, hoping to make it easier to find for others.
After some Android update, the OS started marking regular WiFi access points as "mobile hotspots". The Photos app (and possibly others) was configured to only upload stuff when on WiFi (not mobile data) connections. Because of this and the fact that my regular wireless connection was marked as a mobile hotspot, uploads were paused.
To fix the issue, all you have to do is go to
Settings > More > Data usage > Options menu > Mobile hotspots and then unmark your regular WiFi connections as mobile hotspots.
Here's what the path looks like on my phone. First, you go to
Settings. From there, the
More section contains
Open the options menu and go to
Uncheck the corresponding WiFi networks.
Now restart the Photos app and everything should work as it used to.