This error happens when Chrome updates its security policies and no longer recognizes older CRX file formats.
Firefox uses a separate add-on ( idmmzcc2.xpi ), not idmgcext.crx .
Here are some of the most frequent issues and their solutions: idmgcext.crx
If you see an error about "Manifest version," it means your IDM software is outdated. Update IDM to the latest version to get a compatible .crx file.
Open your browser's page (type chrome://extensions in the address bar). Enable Developer Mode (toggle in the top-right corner). This error happens when Chrome updates its security
C:\Program Files\Internet Download Manager\idmgcext.crx Step-by-Step: How to Install idmgcext.crx Manually
: JavaScript code to interact with the popup.html. Update IDM to the latest version to get a compatible
Most of the time, IDM installs this extension automatically. However, Google Chrome’s security policies or browser updates often disable or remove it. When this happens, IDM stops catching downloads, and you're left with the browser's slow, basic download manager.