The new Edge is based on Chromium and it allows you to install any and all Chrome extensions in Edge. If you try installing themes though, you can’t. This is to be expected because while Microsoft is building Edge on top of Chromium, it is making modifications to it. This is one of them but you can work around it and install Chrome themes on Chromium Edge.
In order to install Chrome themes on Chromium Edge, you need to get the theme file, and install it as an unpacked extension.
Get theme file
In order to get the theme though, you’re going to have to use Chrome, and a Chromium theme called Get CRX. Install it and then, in Chrome, visit the theme page in the Chrome Web Store and click the GET CRX extension’s icon next to the URL bar.
Select the Get CRX of this extension option, and that will download the extension’s CRX file.
Install on Chromium Edge
Open Chromium Edge and click the more options button at the top right. Select Extensions from the menu. On the extensions’ page, enable the Developer Mode switch at the bottom left.
After that, drag & drop the CRX file onto the extension’s page and it will be installed.
The themes look as good as they do in Chrome.
Uninstalling the theme is a bit tricky since we’ve used a bit of a workaround to get it in the first place.
First, close Edge. Open Task Manager and make sure no instance or service that’s related to Edge is running. If you see anything Edge related, select it and end it.
Open File Explorer and navigate to the following location;
C:\Users\YourUserName\AppData\Local\Microsoft\Edge Dev\User Data\Default
In the Default folder, look for the Preferences file. Open it with Notepad or any other text editor of your choice. Use the find feature to look for ‘theme’.
You will find a line like this;
The “aghfnjkcakhmadgdomlmlhhaocbkloab” bit is the ID of the theme you installed. It will differ based on the theme that you’ve installed so it’s not going to match the example. You need to delete it all so that the line looks like this;
Save the change, and then open Edge. The theme will be gone. You might see a message in Edge saying it didn’t shut down properly. This is likely a result of closing an Edge related process from Task Manager.