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How to change default email provider when mailto is not a content type in applications

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  • Last reply by sillynoa

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I recently installed outlook on my machine. Now instead of Gmail as my default email it uses outlook and I want to change it back to Gmail but I do not have Mailto as a content type in apps. Please help.

I recently installed outlook on my machine. Now instead of Gmail as my default email it uses outlook and I want to change it back to Gmail but I do not have Mailto as a content type in apps. Please help.

Chosen solution

When I create a new blank Firefox profile, mailto is there by default, so perhaps at some point it got deleted from your download handler/application preferences file. That file can in theory be edited, but since the format is not well documented, it might be simplest to rename that one and have Firefox generate a new one.

Here's how:

Open your current Firefox settings (AKA Firefox profile) folder using

Help > Troubleshooting Information > "Show Folder" button

Switch back to Firefox and Exit

Pause while Firefox finishes its cleanup, then rename mimeTypes.rdf to something like mimeTypes.old.

Restart Firefox and check Options > Applications again. Any luck?


Also, your Firefox reported itself to the forum as version 17, which is no longer secure (Mozilla discloses security flaws after each new release). Is something holding you back from upgrading to Firefox 20? Please let us know so we can suggest solutions or workarounds.

If Help > About Firefox shows Firefox 20.0.1, you may need to clear the preference that is misreporting your version number. See: How to reset the default user agent on Firefox.

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Chosen Solution

When I create a new blank Firefox profile, mailto is there by default, so perhaps at some point it got deleted from your download handler/application preferences file. That file can in theory be edited, but since the format is not well documented, it might be simplest to rename that one and have Firefox generate a new one.

Here's how:

Open your current Firefox settings (AKA Firefox profile) folder using

Help > Troubleshooting Information > "Show Folder" button

Switch back to Firefox and Exit

Pause while Firefox finishes its cleanup, then rename mimeTypes.rdf to something like mimeTypes.old.

Restart Firefox and check Options > Applications again. Any luck?


Also, your Firefox reported itself to the forum as version 17, which is no longer secure (Mozilla discloses security flaws after each new release). Is something holding you back from upgrading to Firefox 20? Please let us know so we can suggest solutions or workarounds.

If Help > About Firefox shows Firefox 20.0.1, you may need to clear the preference that is misreporting your version number. See: How to reset the default user agent on Firefox.

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Worked, thank you for making my day better!