I wish you would have told me you weren't using WIndows Mail for this when I gave you steps to troubleshoot it and kept referring to it giving you duplicate notifications.
Is ti possible you're using more than one browser to open Gmail, like Chrome and Edge? That could explain two notifications.
While you have me here we might as well fix your Mail app which isn't that hard to do:
I will give you every possible repair for Mail so at least something will work. Even if you've tried some fixes try them again in this sequence:
- Do you know when this started? if so see if you can System Restore to a point before the problem started:
https://www.windowscentral.com/how-use-system-r...
System Restore is your first line of defense and can take you back to a point before a problem began. If it doesn't help then you can undo it. Read about it first in the tutorial above and then try restoring to just before this started. If System Restore is not enabled on C drive do that now so it's available in the future.
If the problem repeats or System Restore doesn't work then check which Windows Updates were installed at Settings > Update & Security > Windows Updates > Update History, uninstall them there or System Restore again, then immediately check for and block the Updates with the Hide Updates tool explained here: https://www.tenforums.com/tutorials/8280-hide-s...
- What often works to fix the Mail app is to go to Windows 10 Mail Settings (gear icon at bottom of Inbox) then Manage Accounts, then choose the problem account(s), then Delete the Account.
Restart PC and retrace that path to add the account back. Make sure the Sync settings are as desired for how far back you want mail Downloaded from, whether to include Calendar and Contacts (People app). See this setup guide to make sure you get everything set as you like: https://www.windowscentral.com/how-get-started-...
- If that's not enough then Reset the Mail app at Settings > Apps and Features > Mail & Calendar > Advanced Options > Reset. Restart PC.
- If that doesn't work then re-register the app from Option Two here: http://www.tenforums.com/tutorials/3175-apps-re...
- Finally if nothing else works uninstall the Mail and Calendar app in Settings > Apps > Apps & Features, restart PC, then reinstall from Microsoft Store app > Hub (three dots at top right) > My Library.
- If you have broader performance problems go over this checklist to make sure the install is set up correctly, optimized for best performance, and any needed repairs get done: http://answers.microsoft.com/en-us/windows/wiki...
Start with Step 4 to turn off Startup freeloaders which can conflict and cause issues, then Step 7 to check for infection the most thorough way, then step 10 to check for damaged System Files. Then continue with the other steps to go over your install most thoroughly.
- If nothing else helps then run a Repair Install by installing the Media Creation Tool and choosing from it to Upgrade Now. This solves many problems and will also bring it up to the latest version which you need anyway and by the most stable method. http://windows.microsoft.com/en-us/windows-10/m...
I hope this helps. Feel free to ask back any questions and let us know how it goes. I will keep working with you until it's resolved.
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