Even though you have taken no action to prevent it, nothing happens when a user presses Synchronize on the Internet Explorer Tools menu.
NOTE: This user does NOT have this problem when they log on to a different computer.
This behavior is symptomatic of the mobsync.dll library becoming unregistered (regsvr32 /s /u mobsync.dll).
To resolve this problem, an administrator can register the mobsync.dll library:
1. Open a CMD.EXE window?
2. Type the following command and press Enter:
regsvr32 /s mobsync.dll