The Bosch Video Client is a 32bit application, CFM 5.50 and newer are 64bit applictions. 32bit applications can only R/W 32bit files (where as 64bit applications can R/W to both 32 & 64bit files), so in order for BVC to access the CFM database, this database also needs to be 32bit.
If you need to configure newer devices with newer FW, you will need to install the relavant CFM version (e.g. CPP 7.3 Camera with FW 7.10.xxxx would require min CFM 6.20.xxxx), by installing the new CFM this will upgrade the original database to 64bit.
Leading to an issue that BVC can not open the database!
Reinstall CFM <5.5.x once more which will cause the database to be migrated back to 32bit.
Strong database encryption must not be activated, otherwise BVC will fail to start.