@qbteachmtNo, it is you who are wrong. BTW, I have a PhD in computer science so I may just know what I am talking about.

"This is a Relational Database and there are associated utility files that are Live Updated while you work. It isn't just the .qbw that is Updated. Unlike Word and Excel, while you work on a data file, it is not Loaded into local memory."

That makes zero difference. Most software "live updates" files on disk"while you work". Every program that has preferences that you can alter, for example. It doesn't matter whether the software has an embedded relational database. What is required is reliable file-locking semantics, which One Drive has if only a single user is accessing the files.

"The file is Managed; you didn't even tell us if you want Concurrent Sharing or just two different computers accessing the files individually. We can help you learn, but you would need to ask."

Neither. I use QB in single-user mode. There is only ever one instance of QB accessing the files at a times. Which is why having my QB file on One Drive works just fine. What doesn't work is the backup process. I am unable to open any of my previously backed up versions and it does not matter whether I back up to the cloud (One Drive), local disk, removable disk, etc.

It is clear that Intuit have built in some kind of protection that prevents this scenario. The only motivation is  that they offer their own (paid) hosted service that they want to force their customer to use.

"Let's try this, again: You can work on a DropBox file that is On Your Computer and sync'd to the Cloud. You cannot work on the Dropbox copy and expect someone else to also use it. "

I don't expect someone else to use it. As above, I am only using QB in single-user mode. It works just fine, *until* it comes time to restore a backup which does not work.

""Unfortunately, intuit do not tell you that they cripple their software so you can't run on a cloud drive."

Yes, this is in the support articles"

Ah, so we're supposed to read thousands of support articles before using the product? If so, Intuit really should tell you that before you buy: "Warning, please spend a month reading all the QB support articles otherwise you risk being unable to open your backups." Might lose a few customers that way though.

"You can do whatever you want to, but if you want to Learn how to use tools, you pay attention to what people are telling you. "

I heard what you were telling me. Something about QB having a magical relational database that means it can't possibly live on a cloud drive (wrong). Something about other programs being intrinsically different because they load all their data into memory and never have to access disk (wrong).

You are correct that QB apparently does not work on a cloud drive, but not for the reasons you give. It doesn't work because Intuit deliberately prevent it from working.