I struggled for more than a month to overcome this error
Not able to delete feed tracked changes when the chatter was enabled in Salesforce environment (Sandbox)
and my sandbox size was just 10 MB and it has occupied around 11.3 MB for these feed tracked changes whenever i was
loading account or contact records in the sandbox thru data loader or thru enterprise wsdl.
So i was not able to create even a single record for testing.
Then deleted all accounts and contacts and then tried. Inspite of that it dint work.
At last, I refreshed the sandbox and the issue was resolved.
I got my full 10 MB free space :)