Mountain Duck

Mountain Duck 5.3 and later runs natively on Windows 11 for ARM.

Managing access to Amazon S3 across multiple AWS accounts and users has traditionally required juggling access keys, secret credentials, and complex IAM policies. With support for AWS IAM Identity Center (formerly AWS Single Sign-On) now available in Cyberduck 9.5.0 and Mountain Duck 5.3.0, connecting to S3 has never been easier or more secure.

What is AWS IAM Identity Center?

AWS IAM Identity Center is AWS’s centralized access management solution that lets users sign in once using their existing corporate credentials—whether that’s through Okta, Microsoft Entra ID (formerly Azure AD), or other identity providers. Instead of managing permanent access keys, users get short-lived credentials that automatically expire, significantly improving your security posture.

Why Use IAM Identity Center with S3?

Traditional S3 access requires creating and managing AWS access keys for each user. These long-lived credentials pose security risks if accidentally exposed or shared. IAM Identity Center solves this by:

• Single Sign-On: Users authenticate once with their corporate credentials
• Short-lived credentials: Temporary credentials that automatically expire and rotate. No more permanent access keys to manage or rotate
• Centralized management: Control access across multiple AWS accounts from one place

Getting Started

Setting up IAM Identity Center authentication for S3 requires two main steps:

1. Configure AWS IAM Identity Center

First, enable IAM Identity Center in your AWS account and configure your identity source. You can use AWS’s built-in directory or connect to an external identity provider like Microsoft Entra ID or Okta. Create a permission set that defines what S3 resources users can access—for example, read-only or full access to specific buckets. Add users through IAM Identity Center (or sync them from your external identity provider) and assign them to AWS accounts with the appropriate permission sets. Users will receive an invitation to set up their access to the AWS access portal.

3. Connect in Cyberduck or Mountain Duck

Creating a connection is straightforward:

1. Create a new bookmark and select AWS S3 (IAM Identity Center) from the protocol dropdown
   
2. Provide your SSO region and start URL when prompted
3. Authenticate through your web browser using your corporate credentials
4. Approve access to Cyberduck or Mountain Duck in the AWS portal
5. Choose the AWS Account ID shown when your user has access to multiple accounts and the Permission Role Name if more than a single permission set is configured

The browser will redirect back to the application, and you’re connected—no access keys to copy or store.

Streamlined Workflow with AWS CLI Integration

For teams already using the AWS CLI, Cyberduck and Mountain Duck can read configuration directly from your ~/.aws/config file. Simply configure your profile once with aws configure sso, allowing you to skip the manual input.

Get Started

AWS IAM Identity Center support is available now in Cyberduck 9.5 and Mountain Duck 5.3. For detailed setup instructions and configuration options, check out our complete tutorial.

Version 5 is now available in the Mac App Store as a subscription instead of a perpetual license. If you previously purchased Mountain Duck in the Mac App Store, you are eligible to run version 5 with no limitations for up to one year after your purchase date before you are required to purchase a monthly or yearly subscription.

Unfortunately we cannot distribute version 4 any longer in the Mac App Store and it is not possible to support subscriptions through the Volume Purchase Program (VPP) in the Apple Business Manager or Apple School Manager. We advise to use a different solution to distribute software for users and switch to perpetual licensing we offer for Mountain Duck outside the Mac App Store.

The new application icon designed by Katharina Hagemann now comes in three variants for macOS 26 Tahoe including Dark and Mono variants. We have decided to make it squircled to fit into the new icon paradigma. The changes will be available in version 5.1.

New Status Bar Icons

Also the status bar icon in the status bar on macOS and the system tray on Windows as the main user interface to configure Mountain Duck has been revamped to visually fit better and show sync progress with rotating arrows.

We are thrilled to announce Mountain Duck 5, the premier choice to mount server and cloud storage as a disk in Finder on macOS and the File Explorer on Windows. Version 5 is a solid major upgrade in development for several years with many new features and refinements, including a new Integrated Connect Mode, storage-independent file versioning support, and SMB connections.

New Features

Integrated Connect Mode

Mountain Duck 5 features a new Integrated connect mode using native APIs on Windows & macOS to integrate in the file explorer. No device driver installation or network mount required. The connect mode delivers significantly faster file write performance and file operations that match the speed of local disk operations, and a user experience similar to OneDrive on Windows or iCloud Drive on macOS but with any cloud storage provider of your choice.

Windows Search and Spotlight on macOS can be used to search for files on remote storage in Integrated connect mode.

See also the blog post Integrated Connect Mode for this feature.

SMB Support

As already available in Cyberduck, Mountain Duck 5 expands its protocol support with the addition of SMB (Server Message Block), enabling seamless connectivity to Windows file shares, Linux Samba, macOS File Sharing & Azure File Shares.

See also dedicated blog post SMB Protocol Support for this feature.

Activity Window

Track and cancel currently running sync operations in the new Activity panel available from the status bar (macOS) or tray (Windows) menu. It shows all running operations on files, pending sync tasks as well as any pending mount process.

Custom Versioning

The new Custom Versioning feature allows to safeguard and restore previous file versions. The previous version is stashed away before overwriting a file.

The option is available for all protocols with no support of file versioning such as FTP, SFTP or WebDAV ensuring your files are protected with version history regardless of the underlying storage protocol. File versions can be view and restored in the Info window.

See also the blog post Custom Versioning for this feature.

Pricing

Version 5 is the first paid upgrade after version 4 debuted in June 2020 with 17 free minor updates released since. Users with a license for version 4 receive an upgrade discount between 20% to 100%.