iPhone 4, attempted update v 4.3.5 to v 5
Windows 7 pro
Get the error "An error occurred while backing up this iPhone (-5000). Would you like to continue to update this iPhone? Continuing will result in the loss of all contents on this iPhone." Continue Cancel.
I hit cancel.
Did iTunes > Edit > Preferences > devices > deleted previous backup (as was suggested in a post) - no change
did computer reboot, - no change
restart iPhone - no change
Microsoft Security Essentials issue.
Open up MSSE
Settings > Real Time Protection
UNCHECK turn on real time protection
run iOS5 update - all good
go back into MSSE and turn ON real time protection again.