I am experiencing a problem uploading any file in several DNN installs that are on the same server.  Two installs are Ver 4.9.5 and one is 5.6.1.
This began about 6 weeks ago - no changes were made to the DNN installs.

When anyone attempts to upload a file via either the file manager or the repository, the file gets created on the destination, but the system aborts the upload and produces an error indicating that there is not enough room on the disk.  The filename is listed in the repository, but usually as 0 length (sometime it is 4092, but usually 0.

A few facts:
1.) There is enough room on the disk, and I am nowhere near my hosting limits.
2.) the hosting provider says that the ASP Net identity for each has full permissions for the folder structure of each site(not sure how I can verify this remotely)
3.) module cache provider is set to Memory
4.) Cache setting: moderate
5.) authenticated cachebility: ServerAndNoCache
6.) Page State Persistence: Page

Does anyone have any guesses as to what may be happening?

Thank you for responding:
I have compression turned off.  I have asked the hosting provider about the virus scanner, but I don't think that is it, since the file gets partially written, and I have no issue with FTP uploads.  I have asked for, but not seen any error logs generated by the server.  I strongly suspect that there is something in the way that the server is configured that is causing this.