How to Load an Unpacked Extension in Chrome (and When to Skip It)

CRX Starter Team · Updated Oct 31, 2026 · 6 min read

Short answer

To load an unpacked extension in Chrome, unzip it into a folder you’ll keep, open chrome://extensions, switch on Developer mode, click Load unpacked and pick the folder that contains manifest.json. Chrome runs it straight from that folder. If you’re not editing the code, installing the .zip or .crx with CRX Starter skips the folder and Developer mode.

Load unpacked is Chrome’s own way to run an extension that isn’t in the Chrome Web Store: you point Chrome at a folder, and it runs whatever is inside. Developers use it every day while they build. Everyone else usually meets it in a README — "unzip, turn on Developer mode, click Load unpacked" — for a .zip like shelf-notes-0.9.2.zip from a GitHub release.

Here are the steps, the errors people hit most, and when you don’t need the unpacked route at all.

On this page

What you need
Steps
Common Load unpacked errors
Load unpacked vs installing the ZIP or CRX directly
Handing a build to testers? Share an install link
Questions

What you need

The extension as a .zip, a .crx or a folder that contains manifest.json
Chrome on a computer where you’re allowed to turn on Developer mode
A folder you’ll keep — Chrome runs the extension from it

Steps

1
Unzip it into a folder you’ll keep
Extract the .zip somewhere permanent, such as Documents/extensions/shelf-notes, not your Downloads folder. Chrome doesn’t copy the files: if you move or delete the folder later, the extension stops working. Have a .crx instead? Copy it, rename the copy to .zip and extract that.
2
Open chrome://extensions and turn on Developer mode
Type chrome://extensions into the address bar, or open the menu → Extensions → Manage Extensions. Switch on Developer mode at the top right. Three buttons appear: Load unpacked, Pack extension and Update.
3
Click Load unpacked and pick the folder with manifest.json
Click Load unpacked and select the folder that has manifest.json directly inside it. Many release ZIPs extract to a folder inside a folder; pick the inner one. Chrome adds the extension at once — there’s no permission prompt for unpacked extensions, so read the manifest first if you don’t know the author.
4
Pin it, and reload after changes
Click the puzzle icon in the toolbar and pin the extension. If you change any files in the folder, press the reload arrow on its card in chrome://extensions. Leave Developer mode on: switch it off and Chrome turns unpacked extensions off with it.

Common Load unpacked errors

What Chrome says	What it usually means	Fix
Manifest file is missing or unreadable	You picked a folder without manifest.json directly inside	Pick the inner folder, or the build output folder (often dist or build)
Could not load manifest	manifest.json has a typo or isn’t valid JSON	Download the release again; don’t edit the manifest by hand
An error about the "manifest_version" key	There’s no manifest_version — often a source folder, not a built extension	Use the release asset the author built for installing
An error or warning about Manifest version 2	It’s an old MV2 extension	Ask the author for a Manifest V3 version; Chrome no longer runs MV2
The Load unpacked button is missing	Developer mode is off, or an administrator has disabled it	Switch Developer mode on; on a work computer, ask IT

Load unpacked vs installing the ZIP or CRX directly

Load unpacked is built for developers who edit the code and reload. If you only want to use the extension, CRX Starter takes the .zip or .crx as it is. You install the extension from the ZIP or install the .crx in five steps; either way it runs inside CRX Starter, which comes from the Chrome Web Store.

	Load unpacked	CRX Starter
Accepts	A folder	The .zip or .crx as it is
Developer mode	Must stay on	Off
Folder to keep on disk	Yes	No
Permissions shown before it runs	No — it loads at once	Yes — sites, browser features, own settings
Edit files and reload	Yes — what it’s for	No — drop a new version in
Warning when Chrome starts	Possible — see why Chrome warns about developer mode extensions	No
Several at once	Yes	One package at a time

If you’re the developer, asking twelve testers to unzip, switch on Developer mode and load your build is where most of them get stuck. If the build is Manifest V3, host the .crx or .zip at an https address and share a crxstarter.com/add link instead. Only download_url is required; name and by appear on the check, update_url turns on daily update checks, and success_url says where to send people after installing.

An install link broken into its parts: crxstarter.com/add with download_url required, and name, by, update_url, app_id, icon_url and success_url optional. — Fig. Only download_url is required.

Example: https://crxstarter.com/add?download_url=https%3A%2F%2Ftools.acme-desk.example%2Fticket-peek-1.4.0.crx&name=Ticket%20Peek&by=Acme%20Support. People with CRX Starter go straight to the check, folded into one line, with an Install button; people without it are sent to add CRX Starter first, and crxstarter.com/ready picks the install back up.

Ticket Peek opened from a crxstarter.com install link: From shows one-click install and published by Acme Support, the check is folded into one line, and the button reads Install. — Fig. What a tester sees after opening the link.

Your responsibility. If you share a crxstarter.com/add link, you’re responsible for the package behind it, and you must not suggest that CRX Starter made, reviewed or endorses it. If you can wait for store review, an unlisted Chrome Web Store listing is the most standard route.

Questions

Why does Load unpacked say "Manifest file is missing or unreadable"?

The folder you picked doesn’t have manifest.json directly inside it. Open the folder: if there’s another folder in it, pick that one. If you downloaded "Source code (zip)" from GitHub, it may need a build step first.

Will an unpacked extension update itself?

No. Download the new version, replace the files in the same folder and press the reload arrow in chrome://extensions. Keeping the same folder keeps the same extension ID and its saved data.

Can I load unpacked on a work computer?

Only if your administrator allows Developer mode. Many managed Chrome setups turn it off; then ask IT to install the extension for you by policy. CRX Starter isn’t a way around that.

What you need

Steps

Unzip it into a folder you’ll keep

Open chrome://extensions and turn on Developer mode

Click Load unpacked and pick the folder with manifest.json

Pin it, and reload after changes