The full error message reads:

Syncing failed. Error: The syncing process for the user: _____ and database: _____ failed. The error is: Dynamic SQL Error

SQL error code = -206

Column unknown

USERS.HHCUSERNAME

At line 1, column 113.

In order to resolve this, you will need to complete the following:

1. Ensure that Handheld Contact is closed on the PC/server.
2. Go to: C:Program Files(x86)Handheld ContactHHC Enterprise Edition. Note: If you have v4.2.10.0 or lower, the location is C:Program Files(x86)KeystrokeHHC Enterprise Edition.
3. Look for a file named 'HHCSYNCLOG.FDB'. Cut it and paste it into another location (Eg. Desktop).
4. Go back to the Handheld Contact download/upgrade file that was just used. If you do not have it, it can be obtained from HERE.
5. Select the ACT! version and download/run the file. When prompted, choose to "Repair' the installation.
6. Once finished, click on Handheld Contact and open it. Try syncing again.