I had the same stuck at 95% experience two days ago, but it disappeared after reboot. I use deepFreeze, meaning all the changes from that update were wiped at reboot. Maybe there are occasional stinker updates.
Did you check if there was an UAC prompt at the taskbar? (shield symbol; "consent.exe" in task manager)?
If not, maybe you need to run client loader as administrator (with administrator rights) while it inställs the update. (After the update, exit client loader and start it normally so it doesn't run with administrator prvileges unnecessary.)