Logi Options+ won't launch on my new MacBook Air running macOS Sequoia 15.6.1

The spinning launch screen usually means the background service isn’t able to initialize properly, which often comes down to a permissions or system extension problem rather than just the app itself. Since you’ve already tried reinstalling and tinkering with Input Monitoring, you’ve covered the basics, but there are a few deeper steps you can try.

First, make sure you’ve completely wiped all traces of the app before reinstalling. Use the Logi Options+ uninstaller (inside /Applications/Utilities/Logi Options+), then manually delete any leftover files in:

• ~/Library/Application Support/LogiOptionsPlus
• ~/Library/Preferences/com.logi.optionsplus.plist
• ~/Library/Logs/LogiOptionsPlus.

Next, after a restart, reinstall the latest version directly from Logitech’s site. When you open it for the first time, approve every prompt in System Settings → Privacy & Security (Accessibility, Input Monitoring, Files & Folders, Full Disk Access if requested).

Lastly, if it still hangs, check Activity Monitor for a process called Logi Options+ Daemon. If that isn’t running (or is stuck in “Not Responding”), try manually launching it from /Library/Application Support/LogiOptionsPlus/logioptionsplusdaemon.app.

Unfortunately, I do not have the MX Master 3S, but an older MX Master model so I won't be able to verify if the following will actually work ... but this is from my notes:

Logi Options+ needs a full suite of permissions to drive gesture functionality. Head to System Settings → Privacy & Security, and ensure Logi Options+ (or Logi Options Daemon) is enabled in all of the following:

• Accessibility
• Input Monitoring
• Bluetooth
• USB Accessories
• Login Items (must be allowed so the service launches at startup)
• Screen & System Audio Recording (only needed if you're using features like the Screenshot or Presentation Remote)

After granting these permissions, especially for Input Monitoring, make sure to quit and relaunch Logi Options+ so everything takes effect.

A number of users report that installing or updating Logi Options+ can unintentionally disable macOS trackpad gestures—like swipe to go back/forward in browsers. In many cases, that’s the root issue.

So go to System Settings → Trackpad → More Gestures, and make sure the relevant gestures (e.g. swipe between pages) are turned on.

Finally, If gestures still aren’t working after resetting permissions:

• Try uninstalling and reinstalling Logi Options+.
• Remove your MX Master 3S from Bluetooth, re-pair it to reset the connection.