.part files are temporary files created during upload / download.
When you upload a large file, DriveHQ client software (FileManager and Online Backup) uploads the file in chunks. Before the upload completes, DriveHQ server creates a temp file FILENAME.part, which saves the partial file info.
.part files are used for resuming interrupted downloads / uploads. If network connection dropped, or if a user manually stopped the upload / download, the partial file will be kept, allowing the user to resume it later (without restarting the upload / download from the scratch.)
if you see a file with .part extension, it means the file has not been uploaded / downloaded completely. In this case, you need to retry upload / download to finish it. If the file is uploaded by another user, then please contact that user to resume. When it finishes uploading / downloading, the .part file will be automatically renamed to the real file name.
You should not manually rename a .part file. You can delete a .part file if needed.