01
Download the disk image
Download NetBlocker from this website. The file is a signed and notarized DMG for Apple silicon Macs.
Use the copy from netblocker.app so you receive the current public release.
Installation guide
From download to protection in a few minutes.
NetBlocker uses a macOS Network Extension, so the first launch includes one system approval controlled by you.
02
Move NetBlocker to Applications
Open the downloaded DMG, then drag the NetBlocker icon onto the Applications folder shown beside it.
This step matters: macOS will not activate the Network Extension while NetBlocker is running from Downloads, the disk image, or a temporary folder.
03
Open the app
Open Applications in Finder and double-click NetBlocker. On the first launch, macOS may confirm that the app was downloaded from the internet. Choose Open.
04
Approve the Network Extension
When macOS asks, allow the NetBlocker Network Extension. If you dismissed the prompt, open:
- System Settings → General → Login Items & Extensions
- Open Network Extensions
- Enable NetBlocker and authenticate with Touch ID or your Mac password if requested
The approval belongs to macOS. NetBlocker cannot silently enable its own extension.
05
Turn on protection
Return to NetBlocker and use the protection switch in the header. The status changes when the filter is ready.
If the switch remains unavailable, quit NetBlocker completely, reopen it from Applications, and confirm the extension is enabled in System Settings.
06
Drop in an app
Drag an application from Finder onto the drop area. It appears in the blocked list together with any related components NetBlocker can associate confidently.
Quit and reopen the newly blocked app once. NetBlocker stops new connections; this closes connections the app already had open.
Still need help?
Tell us your macOS version, Mac model, and what the NetBlocker status says. Never send passwords, license keys, or other secrets.