For several months I’ve lost the ability to categorize transactions in the mobile app. All of my categories are gone and there is no option or ability to add them back.

Hello @mickeec3 

This may sound frivolous, but one possible solution might be to clear the app cache or uninstall and reinstall the mobile app to refresh the data and settings. Or make sure your app is updated to the latest version, as bugs like this are sometimes fixed in updates.

If that doesn't work, another option is to access QuickBooks through a web browser instead of the mobile app and check if your categories are visible there. If they are, it could confirm that the issue is specific to the app.

I appreciate you for reaching out to our customer service, @mickeec3. Allow me to join this thread and help how we can fix your categorization error. 

To start, you can perform the troubleshooting and workaround provided by @JohnBishop1. Let me get into details on how to do this. 

Firstly, ensure that your mobile app is up-to-date. If everything is good, let's proceed with troubleshooting your mobile app. 

iOS:

1. Go to Menu ☰ and tap Help & Feedback.
2. Tap Refresh Data.
3. Tap Refresh to confirm.

Android:

1. Go to Menu ☰, then tap More Options.
2. Tap Settings, then Refresh Data.
3. Tap YES to confirm.

Alternatively, you can uninstall and reinstall the application to troubleshoot your mobile app further.

If the issue persists, I recommend contacting our QuickBooks Online Support Team again so that you can receive an update about your case.

In the meantime, you can check your categorized transactions through a web browser and do your categorization there. 

Once done, you can reconcile your accounts to ensure they consistently align with your bank and credit card statements. 

The Community is always open if you have further concerns about your categorized transactions. Stay safe.