The error message ‘Thread was being aborted’ means one of two things.  

1.) You have corrupt data on our server that was added to the phone and it is trying to sync back to the ACT! database. 

2.) You have some kind of firewall, proxy server, virus scanner, VPN, etc that is blocking Handheld Contact from connecting to our HHC Servers. 

You may need to add some files to the exceptions list of the firewall/virus scanner.  They are:

C:\Program Files\Handheld Contact\HHC Enterprise Edition\HHCService.exe

C:\Program Files\Handheld Contact\HHC Enterprise Edition\HHCServiceMonitor.exe

C:\Program Files\Handheld Contact\HHC Enterprise Edition\MuPlugIn.exe

The location could also be found within C:\Program Files(x86)\Handheld Contact\HHC Enterprise Edition is you have Handheld Contact v4.x.x.x or lower.

Once that is applied, restart the Handheld Contact service and try syncing again.

Note: Another solution that has been used on some customers which has worked is adding a login to the Handheld Contact Service.  See this LINK for exact details.  If the login works successfully, then you shouldn't have any error messages appear and restarting the Handheld Contact Service will work without problems.