Mountain Duck lets you mount server and cloud storage as a disk on your desktop. With Smart Synchronization, files are synchronized to the local disk when opened to allow offline usage and changes are uploaded in the background as soon as a connection is available. Open remote files with any application and work like on a local volume. Transfer files using Finder to remote servers, fast. Select files and folders to always keep offline on your computer. Other files are downloaded and cached on demand only and otherwise do not take space on your local disk. Encryption for data at rest using Cryptomator interoperable vaults prevent unauthorized access regardless of the server or cloud storage infrastructure.

Based on the solid open source foundation of Cyberduck, all major protocols are supported to connect to just about any server you want. Including FTP, SFTP, WebDAV, Azure Cloud Storage, Amazon S3, Google Cloud Storage, Google Drive, Dropbox, Backblaze B2 & OpenStack Swift.

What’s New

Version 4.3.2

• [Feature] Allow custom session duration for STS (S3)
• [Feature] Support for PreferredAuthentications in OpenSSH configuration (SFTP)
• [Bugfix] Include port number when saving host key fingerprint (SFTP, Windows)

Ratings and Reviews

2.8 out of 5
17 Ratings

17 Ratings

timmattison ,

Like many other cloud mounting apps, this one has issues

Copying files from S3 to Dropbox actually worked quite well. However, I see the disks randomly disconnect, fail to refresh, and just exhibit behavior that makes it generally unusable for anything other than bulk, on-demand tasks.

If you plan on mounting some remote storage (SFTP) to work with an IDE to do development this is probably not a good choice.

Also, I've run into the application hanging when trying to remove files with "rm" via the terminal from S3. There didn't seem to be a way to get the command to exit, even with CTRL-C, but the file did actually delete.

MichaelThwaite ,

One of the best

Extends my desktop to servers, sharepoint, S3 and more, reliably. But don't expect the attached disk to work exactly like your internal disk but, when you take that into consideration and this is one of the best tools out there.

Making an S3 bucket or a SharePoint or Google drive look like a local disk is no easy task. Things you do on a local disk like renaming files, moving a hundred files to a new folder, etc. become far more difficult when the wire between you and the disk is 2,000 miles long!

Take S3 for example, you can't rename or edit files in an S3 bucket yet Mountain Duck makes it seem as though you can - silently re-copying and renaming S3 objects in the background - more like a swan than a duck.

Federmanhoyos ,

Really God But Support ?

I bought the application because its option of offline mode. And so far the application has been working pretty well. The complaint is that I cant open PDF files ( Preview or any other editor ) and write notes in the pdf. Every time I do that I receive a messages telling me that is not allowed and basically force me to save the document with a different name.

I have emailed to the product support, but guess what? No answer at all. Nothing.

Fixing the PDF editing error and fixing his support service I will 5 starts to the product

Developer Response ,

Files opened in and edited cannot be saved at the original location but the message "The original document can't be changed, so a duplicate with your changes has been created" is displayed in the title bar. As a workaround you can set a custom mount point in Preferences → Connection → Mount Location for volumes such as a ~/Volumes/ folder in your home directory. Also refre to our FAQ or known issues at


David Kocher
120.4 MB

macOS 10.12 or later, 64-bit processor


English, Arabic, Bulgarian, Catalan, Croatian, Czech, Danish, Dutch, Estonian, Finnish, French, Georgian, German, Greek, Hebrew, Hungarian, Italian, Japanese, Korean, Latvian, Norwegian, Polish, Portuguese, Romanian, Russian, Serbian, Simplified Chinese, Slovak, Slovenian, Spanish, Swedish, Thai, Traditional Chinese, Turkish, Ukrainian, Welsh

Age Rating
Unrestricted Web Access


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.