Summary
The new DPX 4.5.2 installers are available for new DPX deployments only. For versions prior to DPX 4.5.0 use the DPX 4.5.0 installers to upgrade (see DPX 4.5.0 download on MySupport), then use Autoupdate to update to DPX 4.5.2.
Symptoms
After upgrading to DPX 4.5.2 users are unable to login with error: The keystring is invalid
Resolution
To resolve this Problem please go to:..\Program Files\DPX\
Edit the file:
.ssbe_key
Re-paste your Product Key into the File and save it
Restart the DPX services on the Master server and login again.