I discovered one reason and a solution for one of the many factors contributing to the "low on space" notification. This is particularly relevant if you are using Google Plus (not even the app, just the service itself). I have an unrooted HTC Desire, with all apps moved to SD (when possible) and only rarely got the "low on space" notification. A few days back suddenly without me having installed anything the notification came back. The reason was the massively growing contact storage, from 6MB to 11MB. It turns out that two factors were responsible: a) Google adds all the Google Plus connections into "other contacts" in the Google address book. b) The HTC Desire People application syncs ALL Google contacts, including "other contacts", which is a bug. Other HTC phones allow to select which groups to sync, but not the HTC Desire. The solution is to disable the sync of Google contact, and to re-enable it in a different way: Go to accounts & sync, select Google, and then unselect contacts. Now, delete the data of the contact storage (ONLY IF YOU REALLY USE THE SYNC WITH GOOGLE of course). This will remove the contacts from your phone, but not from the Google servers. Go again to "accounts & sync" and add a new account . Select "Exchange ActiveSync". Enter your Google email/password, and as the server address "m.google.com". Create this new account and start the sync (I had to start the sync two times, then my contacts were back. This results in synchronizing only the group "my contacts". In my case, it is what I wanted (if you need to sync other groups than this one, this solution is not for you). Now, my contact storage is only 1MB, and I can add/change contacts as usual. I hope this is helpful for some of you.