How to: Retrieve partial downloads from a Synology NAS

You may find some downloads get to 99.9% complete and then stop, never to finish. When this happens the likelihood is that the download is complete but has just got stuck, however you can’t see the files as they are still stored in a hidden temp folder called ‘@download’. Follow these steps to retrieve partial downloads from a Synology NAS.

1. Login to the DSM (Disk Station Manager) as ‘admin’ and enable the telnet service under ‘Network Services > Terminal’
2. Create a new share under ‘Privileges > Shared Folder’ and call it temp. Read/Write permissions should be left open, the folder can be deleted when we are finished.
2. Open command prompt in windows and start a new telnet session

telnet: (Where ‘’ is the IP of your diskstation)

3. Enter ‘root’ as the username, press enter
4. Enter your admin password, press enter
5. Type the following

"mount --bind /volume1/@download /volume1/temp"

6. Navigate to the new shared folder in windows (\ entering your user credentials when prompted, you may want to map a drive to it for ease of access.
7. Each of your partial downloads will be located under separate folders, copy the data you require to another folder.

Once you have successfully retrieved the partial downloads, you can stop and remove the downloads via download manager. You may then want to delete the temp folder.

Appendix A: If the telnet command is not recognised you need to first install the telnet service via Add/Remove Windows Components, or if you’re running Windows 7 with the following command (administrator privileges):

"pkgmgr /iu:TelnetClient"

25 thoughts on “How to: Retrieve partial downloads from a Synology NAS

  1. I get stuck on telnet part (W7), but i used WinSCP (part of Altap Salamander, between others) – just simply log to Diskstation (adress: diskstation user:root), go one folder up and voiala: i can browse whole DS, and @download too:


  2. I was wondering why volume 1 was almost full when my two shared folders contained just a few hundred gigs. And I found more than 1 TB of data that Download Station hadn’t deleted after copying the downloaded torrentdata the other disks. And thanks to your trick I didn’t have to do all the deleting in terminal. Ty


  3. Very helpful and let me recover lost downloads. However, when I try and delete the temp directory I get en error saying I have to unmount the file system. Very new to linux – what is the correct syntax for that?


  4. Thank you for the tip!

    After finding the partial download I tried to delete the temp folder in Control Panel > Shared Folder.
    But the Synology says I have to unmount the virtual drive in the shared folder.

    I then tried telnet
    umount /volume1/temp
    but I got a “Operation not permitted”

    Any ideas on how to proceed?


  5. I was searching how to access finished files while torrent is still downloading, you gave me the solution, thank you 🙂


  6. Followed the instruction to type in “mount –bind /volume1/@download /volume1/temp”, the NAS replied “mount: mounting /volume1/@download on /volume1/temp failed: No such file or directory”. Please advise solution.


  7. Thanks ! I was downloading a series of files and needed the one that finished first (that I marked with High Priority) before the rest got in.


  8. Hi, I tried this to recover a 15 GB download and worked like a charm!

    However, when I try to delete the Temp folder, I keep getting a warning saying that I have to unmount the virtual drive in the shared folder.

    How can I do it in telnet?



  9. Very useful, I was looking for this not only for unfinished downloads but also as to check the content of a large file before downloading it all and find eventually having spent hours for downloading something unwanted.
    One thing though I have noticed is that the mapped drive will appear empty next time you reboot you NAS. Is the mount procedure you advised only valid for that session or it should be permanent?



  10. It seems that I loose this mount point after awhile.
    II suspect is that it is not permanently, so during a reboot, the mount is lost.
    Is this correct?
    And, could I add an entry to the fstab file to have it always be mounted, or is there some other way.
    My guess is that the fstab entry would be something like:
    /volume1/@download /volume1/temp ext4 defaults 1 1


  11. I tried a few months ago your solution and it worked but today i tried and when i write the mount command say “mount: permission denied (are you root?)”. I access with the admin user like the another time. You know what is the problem? Thank you!!


  12. In addition, to make this configuration permanent (as it is right now, once you restart the device or do an upgrade the setting is gone), do the following:

    1. create a file called “” under /usr/local/etc/rc.d/
    2. populate this file with the following content:

    case $1 in
    mount –bind /volume1/@download /volume1/temp
    echo -e “Nothing to stop…”

    After this, your configuration should be able to stick…


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