A message appears stating that an error occurred while syncing, with the error number "(-54)". Then it says that I do not have "access privileges" to sync my iPhone and complete the process. All my contacts have been completely deleted. iTunes is not allowing me to restore my phone to a backup before installing iOS5 update.
The -54 error is defined as follows :
Is your computer Authorized ? iTunes -> Store -> Authorize this computer ?
Otherwise you don't have the correct permissions to a file you are trying to use for the sync. Try running the following script to see if it helps. It will unlock all files in your