Why are there numerous unknown files within my OneDrive account?

Question

My OneDrive account is running out of space, and I see there are many unknown files of the same type:

1. Each file is 16.1MB in size
2. Each file has a file name consisting of 64 random alphanumeric characters.
3. When I look at the file contents, it appears to begin with "LZ4" and then empty space.

Does anyone know what these files are, and can I just delete them from my OneDrive?

Answer 1

Hello, thank you for reaching out to Microsoft Q&A.

These could be temporary cache files or files created by a tool or software that uses the LZ4 compression method, and they may have been uploaded to OneDrive. For example, if you're saving those files in the Documents folder, they might be syncing automatically to OneDrive.

Check if you have any third-party tools that use LZ4 compression and verify whether they are generating these files. If any of your applications regularly save data in LZ4 format, deleting the files from OneDrive may affect those applications or their data.

To delete other files that take up your space,

Open an incognito tab and sign in with your Microsoft account here.

https://onedrive.live.com/?view=1&v=managestorage

Select Free Up Space: OneDrive.

Toggle selection for all items.

Click Delete.

Once you have deleted all items from the lists, delete them from the recycle bin folder. You can also delete the LZ4 files if you no longer use any software or tools that save files in this format.

This will permanently delete those files and free up storage in your OneDrive account.

Important: Ensure you have a backup of these files in your local folder before deleting them from OneDrive.

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Additionally, reset OneDrive on your Windows PC by following the steps here.

Reset OneDrive