The feature to install an MSI using Dropbox simply does not work. I've tried it with 2 separate CCleaner Cloud environments, 9 different computers, and 3 different MSIs. It always displays an error in the console that says 'Failed'. When you expand the error, it says 'Unknown error'. What is the reason for this?
Solved: My Dropbox account was banned for a file they thought was malicious lol. I put the MSI in a brand new Dropbox account and everything worked smoothly.
Thanks for letting us know what the cause of your issue was, as it wasn't CCleaner at all then I'll close this thread.