I was annoyed recently because my iPhone Gmail app didn't show the latest saved drafts, and I couldn't for the life of me figure out how to clear the app's cache. I couldn't find any obvious "clear cache" option, and completely closing the app and restarting the iPhone didn't help.
This finally worked for me:
- Open the Gmail app.
- Open the sidebar and open the account list.
- Touch "Manage accounts."
- Turn OFF the account with the expired cache problem, wait a minute or so, then turn it back on.
After turning the account OFF then back ON again, the Gmail cache was cleared. It's still funny how almost every IT problem is fixed with "OFF then ON again." The trick these days is figuring out what exactly to turn off, then on.