Invalid value for 'web_accessible_resources[0]'

What you see

Invalid value for 'web_accessible_resources[0]'. Could not load manifest.

Why it happens

Version 2 took a plain list of files. Version 3 wants a list of objects, each with "resources" (the files) and "matches" (the sites allowed to load them). A plain list in a version 3 manifest stops it loading.

The fix

rightsocket does this Rewrites a plain list as { "resources": [...], "matches": ["<all_urls>"] }, which lets every site load the files, as version 2 did.
You do this If the message ends with "Invalid match pattern", an address in "matches" is wrong: each needs a scheme, a host and a path, like https://example.com/*.

What changed, and when

24 July 2025, Chrome: Chrome 138: Manifest V2 extensions disabled for all users on all channels, with no option to turn them back on. Chrome 139 then removed the enterprise policy that kept them working.

Sources

Chrome for Developers: web_accessible_resources
Chrome for Developers: Match patterns
Stack Overflow: "Invalid value for 'web_accessible_resources[0]'"

Other chrome extension errors

Manifest version 2 is deprecated
Service worker registration failed. Status code: 15
Manifest is not valid JSON
Could not load icon specified in the manifest
Refused to execute inline script (Content Security Policy)
chrome.browserAction is undefined (Manifest V3)
'browser_action' requires manifest version of 2 or lower
'webRequestBlocking' requires manifest version of 2 or lower
Permission is unknown or URL pattern is malformed
Invalid value for 'content_security_policy'
Insecure CSP value in directive 'script-src'