3572473 - The CMS has terminated unexpectedly with exit code 1 when performing BO upgrade

• Below error is encountered during the BO 4.3 upgrade:
  ERROR: Could not establish a connection with any CMS.*_*#*
  ERROR: An unexpected internal error occurred. The CMS has terminated unexpectedly with exit code 1. (FWM 23025)
  *#*_*|ERROR: An unexpected internal error occurred. The CMS has terminated unexpectedly with exit code 1. (FWM 23025)|ERROR: An unexpected internal error occurred. The CMS has terminated unexpectedly with exit code 1. (FWM 23025)*_*#*
  14:32:47.741 ERROR: Could not reach CMS '<host>:6400'.  
• In Windows Event Viewer, the log displays that the user who executed BO upgrade was failed to access CMS DB folder.

• SAP BusinessObjects Business Intelligence platform 4.3 SP4
• Windows

BO 4.3, Upgrade, Windows AD, CMS DB, Access , KBA , BI-BIP-INS , Installation, Updates, Upgrade, Patching , BI-BIP-SRV , CMS / Auditing issues (excl. 3rd Party Authentication) , Problem