Share your experience!
I tried to login to another Gmail account and cleared the data & cache under Manage applications. Ever since then my Gmail isn't loading. When I click on the Gmail widget, it comes up with a black screen - the header says 'Waiting for sync; and another across the middle of the screen that says 'Your email will appear shortly' .
There is nothing else I can do other than close this.
I tried everything under manage applications, cleared data & cache , force stopped all applications, rebooted the phone, etc - nothing works.
Even SE support have given up!
I can login successfully into Gmail account via the Email Widget.
Can someone help (I would reserve the 'factory reset' as the very last option as I had enough trouble sync'ing my phonebook and cant afford to waste more time on it)....
One thing this phone succeeds very well at - wasting the user's time trying to fiddle with the most complicated features any phone can have!!
Backup you data and go for factory reset.
go to settings - - > data synchronisation and see if the Google Mail box (under the Synchronise with Google Mail section) is checked...if not, click on it and you should see the sync icon working..wait for it to finish and then check the gmail app to see if the emails have downloaded...If you leave it checked, gmail will autosync according to whatever frequency you have picked but if you leave it unchecked everytime you open the gmail app you will need to refresh manually to get the emails...hope this helps...
Wow!! Brilliant! Thanks a million!! ... It fixed my problem.
I was worried if it would erase my phone book contacts, but it didnt.
You did what SE support couldnt !
glad to help..amazing what you discover if u tinker about with this phone for long enough 
I had to do a search in the gmail app and from that moment on it worked flawlessly so far.
Had the same proble but switching on 'Auto sync' in settings worked for me.
It's under 'Accounts and Sync'.
Thanks for putting me on the right track. 
Mike.