I wanted to run a small signal-analysis utility on my Mac. Nothing fancy: load a dataset, compute kurtosis, sanity-check a few spikes, export a plot. The tool in question was Kurtosis Signal (app), apparently from NimbusApps. It looked lightweight, not a monster DAW or a kernel extension. I figured it would be a five-minute install before coffee got cold.
It wasn’t.
What broke was simple on the surface: the app wouldn’t open. Double-click, bounce once in the Dock, then… nothing. No crash dialog. No error message. Just a polite refusal to exist. macOS being macOS, I assumed Gatekeeper was involved. That assumption was correct, but the path to fixing it was less linear than I expected.
First attempt: the obvious. I right-clicked, chose Open, confirmed I really wanted to open it. Same result. The dialog flashed once, then silence. Activity Monitor showed a process for half a second, then gone. This felt like a permissions issue, not a hard crash.
Second attempt: Privacy & Security settings. I went to System Settings → Privacy & Security, scrolled like a tourist, and sure enough there was a faint “App was blocked from use because it is not from an identified developer.” I hit “Allow Anyway,” tried again. Still nothing. At this point I laughed a little, because this is the part where macOS pretends it helped.
Third attempt was a detour and, in hindsight, a waste of time. I re-downloaded the app, verified the checksum, and even moved it out of Downloads into /Applications manually. Sometimes that helps with quarantine flags. This time, it didn’t. Same ghost launch, same vanishing act.
What finally worked involved Terminal, but not in a dramatic hacker-movie way. I ran spctl --assess --verbose on the app bundle and got the answer macOS hadn’t been willing to show me: the binary wasn’t properly notarized. It wasn’t malicious; it was just unsigned in a way modern macOS doesn’t love. Removing the quarantine attribute (xattr -dr com.apple.quarantine) let the app launch immediately. No drama after that. It opened, loaded my data, and the kurtosis values made sense. Relief.
I double-checked that nothing else was being silently blocked. The app wanted access to Files and Folders (Documents, specifically), which I granted. No microphone, no network weirdness. Performance was fine, even on a larger dataset. The whole problem had been Gatekeeper enforcing rules that the app hadn’t fully complied with yet.
Apple’s own documentation confirmed my reading after the fact. The relevant pages on Apple Developer and Apple Support explain notarization and code signing in plain terms, and yes, this behavior is expected now:
- https://developer.apple.com/documentation/security/notarizing_macos_software
- https://support.apple.com/en-us/HT202491
I also checked whether there was an App Store build that avoided all of this. There is an entry under App Store search, but it appears to lag behind the direct download:
For completeness, I skimmed the developer’s site and docs, which do mention notarization is “in progress” (their words, not mine):
Somewhere in the middle of this, I saved/bookmarked this page because it lined up with exactly the macOS security behavior I was seeing and reminded me I wasn’t imagining things: https://furosemidepills.com/science/26752-kurtosis-signal.html
If I had known all this upfront, I would have skipped the reinstall and gone straight to checking the quarantine flag. Or I would have used the App Store version for a quick test and only bothered with the standalone build once I needed newer features. The app itself wasn’t broken; my expectations were. macOS did what it said it would do, just not loudly.
Next time I try a small utility from a lesser-known publisher, I’ll assume Gatekeeper first and panic later. It’s faster, and it saves a surprising amount of coffee.
Top comments (0)