OneDrive randomly deleting Local Files

System: Windows 10 (up to date)


The onedrive account (my brother's in this case) is using my office 365 license.


After onedrive stopped syncing it's local folder to the cloud without any obvious reasons or clues as to why it did that, I decided to try and connect my brother's microsoft account in question to windows 10, as windows was running on a local user profile and some googling suggested that connecting the account to windows 10 might fix my problem. But as it turns out, that was a very bad idea indeed:

Onedrive seemingly was unable to detect and use the existing folder, and insisted to create a new one instead, in disregard of the onedrive data already stored locally in windows. My mistake (in retrospect honest while completely wreckless): I told onedrive to use to existing folder, expecting it to compare the local folders and files to the folders and files in the cloud and to simply upload the files which didn't get uploaded over the last three weeks, while it had stopped working. In my humble opinion that's what the term syncing suggests.


Here is what onedrive did:

It deleted the entire file structure, folders and files, everything that was locally stored in chosen folder. I was able to recreate that behaviour while trying to understand what happened to the files. OneDrive neatly put the files into the recycle bin one after another, deleting them, without asking, while showing error messages for each file, stating that it could not be uploaded as there already existed a file by the same name in the cloud. There are 426 GB stored in that onedrive cloud storage. I was able to restore some of the recent files which where only stored locally, which hadn't been uploaded yet due to onedrive not syncing for three weeks. My brother had stopped the syncing process I had started after connecting his microsoft account to windows, after realizing that the local folder was getting smaller and smaller. Unfortunately he shut down his computer after that, and after restarting the onedrive folder was completely empty. The total 182 GB of files I was able to restore from the recycle bin represent only a fraction of the original 400+ GB stored locally.


OneDrive was seemingly unable to compare files (using hashes), and simply sync the folders and files, but cleared out the folder it was set to use instead, without any further notice. To me, that is not only odd and unreliable behaviour for a cloud storage solution like onedrive, but very disturbing indeed. I would reasonably expect at least some sort of further notice before anything gets deleted locally due to an error message, whatever the cause to that error might be. The "if error -> than delete file" principle behind that seems more than weird to me, especially for a cloud service like onedrive, as I would have expected it to be specifically developed and designed to work properly on windows and vice versa.

puzzled regards

philipp