At 10am I could not login via UI3, and investigated. BI was not running and the desktop was at the login screen.
Checking the logs I found...
BI was using 47GB! Normally, my BI using 1.2 GB!Windows successfully diagnosed a low virtual memory condition. The following programs consumed the most virtual memory: BlueIris.exe (676) consumed 47056519168 bytes, NortonSecurity.exe (4812) consumed 270987264 bytes, and explorer.exe (8836) consumed 154300416 bytes.
Reverting back to 5.4.4.8 corrected this.
5.4.5.1 came out this morning at 10am (Maybe to correct the leak). This corrects the memory leak also.