Yes. Check your messages on your SIM as stated . AppMonster - Android app on AppBrain It's called app Monster. works great. All your paid apps will be backed up through google but this gives you one click to install them all from backup on the SD card. hope you get it figured out and do post back when you find the solution.
I'd do a factory reset just back your stuff up like MOTO said. And sense is a nice Rom but nut quiet three yet. But if you wanna try it out let me know if you have any questions. I know it could be a headache if you are new to this.
I had a space issue for a while and finally found that my Email (not Gmail, but the 5 e-mail accounts under the Email app) was using like 90 MB! So I removed all accounts and added them back and the space was only like 4 mb. It's been steadily rising and it's at like 12 mb now. Not sure what to do to keep it from growing like that. But since I cleared out all that space I haven't had a low memory issue and therefore no more text message memory full issues.
You'll get this message, and your texts will get lost, whenever your internal storage drops below 20M. It's stupid and annoying.
Most of the time I run into this problem, it's because some app is using a lot of internal storage for cache. I found an app called Quick App Clean Cache that will show you how much cache space each app is using. If you are rooted, QACC can also clean the caches for you. If not, I think you need to go into Managing Applications and clear each cache manually. The app isn't free, but costs less than $1, and is the easiest way I've found to figure out what you need to clear out.
I have the Nexus One with 2.2.1 and when I go to 'settings' I do not
see 'manage SIM messages'.
Is it in a sub-menu?
When you are in the default Android Message application, select the Menu button and the Settings. You then shoud see "Manage SIM card messages"
I had this same memory problem and had no messages on the SIM and had already deleted all my text message threads. The only thing that fixed it, was uninstalling the Handcent Text app. Then the issue went away, and so far it hasn't returned.