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AppImage is a popular packaging format for Linux systems. You'll often find applications packaged in this format.
Sometimes, when you try to log in to a service’s AppImage through a browser, even though it will report a success and tell you to go back to the app, it actually won’t.
Let me share a quick tip on how to force open external links in AppImage so that you can log into it through a browser.
Make AppImage open external links
Here, I am using an AppImage for Todoist that needs you to log in through the browser.
First, open the app and click on login through the browser button.
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When it asks you to login, enter the credentials and log in.
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Once you successfully log in, it will ask you to open the app in an external app.
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If your System Handler finds the proper app, then there is no issue. If you want to open it in another app of your choice, click on “Choose a different application” link.
Now, click on “Choose” button.
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This will bring you to the file chooser. Select the AppImage of your choice, in this case, Todoist, to open that particular link.
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Click on Select. Once selected, press “Open Link” to open it in the AppImage.
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That's it. You can see the AppImage will be now logged in.
Please note that this is a very specific scenario and you'll encounter it with very few applications.
I hope this quick tip helps you. Please let me know if you have questions or suggestions in the comments.