Glance QuickLook Plugin Not Working or Disabled? Here's What to Use Instead

What's Actually Happening to Glance

Glance started as an open-source, all-in-one Quick Look plugin built by developer Samuel Meuli: one install that covered source code with syntax highlighting, Markdown, Jupyter notebooks, archives, and TSV files. The original repository, samuelmeuli/glance, was archived on GitHub back in November 2020 and never updated again.

The version most people actually have today is a community fork by a developer who goes by chamburr (Han Cen) on GitHub, which rebuilt Glance on the modern Quick Look extension API and kept it working through Big Sur and beyond. That fork is what Homebrew distributes under the cask name glance-chamburr, and it's that specific Homebrew listing, not the app itself, that Homebrew's own cask page now flags as deprecated with a disable date of September 1, 2026.

Glance isn't the only casualty. QLStephen, the long-running plugin that lets Quick Look preview extension-less plain-text files, carries the same deprecated status in Homebrew's official tap. quicklook-json, a smaller plugin for previewing JSON files, has already been disabled outright, one step further along the same path Glance is now on. This is part of a much broader sweep: Homebrew's own numbers put it at 387 of roughly 7,624 casks in the official tap, about 5 percent, flagged for the same reason and given the same September 1 disable date.

Why Homebrew Is Doing This

This traces back to Homebrew 5.0.0, released in November 2025. That update introduced a stricter cask audit: every cask distributed through the official homebrew/cask tap now has to be code-signed and notarized by Apple, and any that fail get marked deprecated for the reason Homebrew's own tooling labels fails_gatekeeper_check. The same release removed the --no-quarantine flag, which previously let a brew install forcibly bypass macOS's Gatekeeper warning for unsigned software on a user's behalf.

Homebrew's maintainers were direct about the reasoning in their own GitHub discussion of the change: they want software installed from an official tap to just work, rather than users filing bug reports for problems that are really Apple's Gatekeeper doing its job on unsigned code. They were equally direct that this isn't Apple pressuring them into it. It's an unpaid, volunteer-run project setting its own quality bar. Homebrew 6.0.0, released in June 2026, confirmed the September 2026 disable date was still on track, so this isn't a proposal anymore, it's a deadline that already survived one release cycle.

The practical reason 387 casks failed at once rather than a handful: Apple's notarization pipeline isn't free. It requires a $99-a-year Apple Developer Program membership and submitting every release through Apple's automated scan. That's a real, recurring cost for a one-person open-source side project like Glance, and plenty of small, genuinely useful utilities in Homebrew's tap were built without it long before this policy existed.

What "Disabled on Sept 1" Does and Doesn't Mean

This is the part worth being precise about, because "disabled" sounds like a remote kill switch and it isn't one.

There's one more wrinkle worth flagging honestly: Glance was never notarized to begin with, which is the entire reason it's on this list. Before September 1, Homebrew smoothed over the resulting Gatekeeper friction for you. After it, installing Glance at all, through any channel, means approving it past Gatekeeper yourself, the same one-time manual step described in the fixes below.

Check Whether You're Affected

Open Terminal and run this to see whether Glance is on your Mac through the cask being disabled:

If neither command returns anything, you either never installed Glance or installed it manually from a downloaded .dmg rather than through Homebrew, in which case this specific cutoff doesn't touch you at all, though the underlying unsigned-binary caveat still applies.

Your Three Options

Side-by-Side Comparison

A Simple Before-Sept-1 Checklist

1. Run brew info --cask glance-chamburr to confirm you're actually affected.
2. Decide: stay on Glance itself (personal tap or direct download) or move to a notarized paid tool.
3. Staying on Glance: brew uninstall --cask glance-chamburr, then brew install --cask chamburr/tap/glance.
4. Switching tools: uninstall Glance, install Looq or Unfold, then confirm the new extension is enabled under System Settings > General > Login Items & Extensions.
5. Either way, doing it before September 1 means zero interruption. After that date the official cask simply won't reinstall if something goes wrong mid-switch, so you lose your fallback.

Where Quick Folder Preview Fits In

None of the tools above, Glance included, ever previewed folder or archive contents, the specific gap Quick Folder Preview is built to close. We're building it as a drag-and-drop, folder-first take on instant preview for Mac, aimed at macOS 11 and later on both Intel and Apple Silicon. It is not available yet, only a waitlist, and it has no bearing on anything in this guide either way.

Sources & Further Reading

Frequently Asked Questions

The Bottom Line

Homebrew disabling Glance's official cask on September 1, 2026 is real, but it's narrower than it sounds. It closes one installation channel for one plugin as part of a 387-cask policy sweep, and it doesn't touch a copy already running on your Mac. If you want to keep using Glance exactly as it is, the maintainer's own tap gets you there in two commands. If you'd rather stop tracking which of your free Mac utilities are notarized and which aren't, Looq or Unfold get you the same previews without the question ever coming up again.

Looking for more Mac productivity guides? Read our full guide to previewing files on Mac without opening them, browse every 1dot.ai guide, or check Quick Folder Preview's product page for the waitlist.