After updating my HTC Desire HD to HTC Sense 3.0 I can’t login anymore to Twitter app 2.1.2 with error message “That account has already been added”. I tried to update the Twitter app to version 3.0.0 but still got the same problem.
A quick Google search found a page on Twitter help center that mentioning a known bug/issue with the same error message as I got. Following the suggestion I uninstalled the update version 3.0.0 and restart my device, alas it doesn’t fix it. I’m stuck with Twitter version 2.1.2 and can’t uninstall it as it’s embedded on HTC sense.
Then I tried to login using another Twitter account which I didn’t added yet to my phone and it works, I can login. It turn out that the problem was on “Accounts & sync” settings, the Twitter sync setting had a problem with login, so the steps that I take to fix it:
1. Go to Settings > Accounts & sync
2. Tap on the Twitter account
3. Tap on Remove account
4. Go to Twitter app and try login again
Those steps should fix the problem and you don’t need to reboot your phone.