Out of the blue all previous conversations in my N9 disappeared, and all new received SMS are stored as empty. The SMS I send are visible for a while, but right after they are sent they show up blank.

I suppose there is a corruption in the database storing messages, but I am not sure how to check it. Other applications are still working fine so it is less likely to be a general filesystem corruption.

This is pretty annoying as new incoming messages can only be read in their notifications.

Any ideas?

Try rebooting your phone and wait a minute or two before opening the messages app then click a few times on the center of the app and your messages should start appearing...

Anyway the most important thing is making sure not to lose any messages so run N9QT Tweak NN-2 and export all of them first...

As long as they are in the database they will get exported even if they don't appear in the messaging-ui...

You can also try exporting using Nokia Suite but the above method is what you should try first...

Thanks for your reply. I have, of course, tried rebooting the device and that doesn't help. Messages remain gone. I'll check the other option you mention, although I'll certainly prefer to check via the command line the status of the database. I suppose messages are stored in the tracker storage and can be checked through sparql in the command line?

OK, so tracker-stats tells me that there are a few thousands IM and SMS messages, so I guess that they are not lost. However they would just not appear in the UI..

The problem with messages are they are linked to tracker but I still haven't found where their database is; they are not in tracker's database...

Hence back them up using the tool above then you can restore them or even do a tracker-reset before restoring them...

This issue can occur due to fastern9 or if you have >2,000 messages on your device...

do some soft reset
press the power button for at least 10 seconds

So this query

Shows me the contents of all past messages but indeed, all the messages since I noticed this issue are listed as (null).

I don't know what fastern9 is, so I don't think it's related. Could you please be more precise on why having more than 2000 messages could cause this?

Apparently the system is supposed to work well with only 2,000 messages...If you sync your messages using Nokia Suite you can see that if you have more than 2000 messages it advices you to allow it to clean up and store those messages on your PC but delete them from your phone...

Its a deficiency of Harmattan from what I see it as...Android too was restricted to 5,000 messages till ICS after which the limit is now 10,000 messages before it starts to lag and causes all sorts of issues...

OK, I see. That's a terrible limitation. I am not sure I have anything I want to delete from my messages, but I'll check if deleting a few helps. Thanks for your insight.