Mount SMB shares on Mac like iCloud Drive.
KastDrive turns any SMB or Samba server into a Finder folder that streams files on demand. Powered by AMSMB2, with SMB 2 and 3 signing, connection pooling, and zero bulk downloads. No more "server interrupted" dialogs.
Free tier: 1 SMB mount, forever — no credit card required
Why KastDrive for SMB on macOS
macOS's built-in SMB client is fine for casual use. KastDrive is built for people who live in their shares all day — designers, editors, and teams with terabytes on a NAS.
Backed by AMSMB2
We drive every SMB connection through AMSMB2, the same battle-tested Swift library powering the most demanding iOS and macOS file apps — fast, native, and actively maintained.
SMB 2 & 3 signing
Full SMB 2.1 and SMB 3.x dialect negotiation with message signing and encryption, so shares over hostile or public networks stay tamper-proof and private.
Connection pooling
Long-lived, multiplexed sessions keep a warm pool of SMB channels open, so opening the tenth file costs the same latency as the first — no renegotiation, no stutters.
Finder, natively
Shares mount through Apple's File Provider Extension API. They show up in Finder sidebars and behave like iCloud Drive — cloud badges, on-demand download, bidirectional sync.
How it works
Three steps from server address to a Finder sidebar you'll forget isn't local.
Add the share
Enter smb://server/share, pick NTLM or Kerberos credentials, and save it to your keychain. KastDrive remembers the dialect and signing preferences.
Mount into Finder
The share appears under Locations in Finder with a familiar blue drive icon. Browse thousands of files without downloading a single one upfront.
Open and edit
Double-click any file to stream it on first open. Save your changes and KastDrive pushes them back over the same pooled SMB session within seconds.
KastDrive vs Mountain Duck for SMB
Mountain Duck mounts SMB through FUSE, so it can't stream files on demand. KastDrive uses Apple's File Provider API backed by AMSMB2 — cloud badges, on-demand opens, native sync.
| Feature | KastDrive | Mountain Duck |
|---|---|---|
| SMB engine | AMSMB2 (Swift, native) | libsmbclient / FUSE |
| SMB 3 encryption | Yes | Partial |
| Online-only files | Yes — cloud badges | No — full download |
| Connection pooling | Yes | No |
| Finder integration | Native File Provider | Kernel extension |
| Price | $0 free / $29 once | $39 + per-year renewals |
Mountain Duck pricing as of June 2026. No affiliation with Cyberduck/Mountain Duck.
Your NAS, finally fast in Finder.
Mount your first SMB share free. Upgrade to Pro for unlimited mounts, bandwidth scheduling, and Cryptomator vaults.