To untrack a topic, I can enter the topic, click the bell button, and change the selection from “Tracking” to “Normal”. This works for individual topics. But how to untrack topics in batch?
Asking because I have changed my tracking status of a category from “Tracking” to “Normal” and would like to also change all topics I’m currently “Tracking” in that category to be “Normal” as well.
Thanks 
Try the following.
Go to your profile, select Activity and then Topics. You should see a list of your recent postings.

Then click on the Topic icon (circled) and you’ll get check boxes alongside your topics.

Select the ones you want to change. Under Bulk Actions
there should be one called Update Notifications
.
This should do what you want, but I’ve never actually used it myself. Please let us know if it works.
Not seeing that icon here?
@halogen2 Unfortunately, there is no such option for TL3 and below.
According to the people over at Meta, the suggestion was to do like this:
Source:
https://meta.discourse.org/t/bulk-actions-for-users-to-change-notifications/369408
Of course, this is only good for new topics not older ones as I believe you wanted.
3 Likes
Sorry, I got ahead of myself and didn’t realise that it’s only available to mods and others at that level.

No harm caused, I hope…