My System Center Virtual Machine Manager 2012 R2 lab deployment crashed on me a while ago. Any attempt to log on prompted the following error ID 1602 :

I restarted the SCVMM Service and the SQL Service successfully, but each time I tried to start the VMM Console, the SCVMM service stopped with the same error prompt displayed above. I did a quick research and came across a Microsoft KB3020448 . It basically describes the problem as occurring if there is an incorrect data type inside one or more rows of the “tbl_VMM_GlobalSetting” table in the Virtual Machine Manager database and recommended running the following SQL Query :

"update tbl_VMM_GlobalSetting set PropertyValue = NULL where PropertyName ='UpgradeTime'"
After running the query against the VMM SQL DB, I restarted the SQL Server service, SCVMM Service and SCVMM Agent service on the management host. After the services’ restart,I was able to login successfully and continue work on SCVMM 2012R2. Hopefully this helps someone.