I have a c.6 year old mythtv database. I recently upgraded from Ubuntu 10.04 to 12.04. This brought a MythTV upgrade from 0.24 to 0.25, which went well.

Today, all my recordings have disappeared. They still exist in the /var/lib/mythtv/recordings folder, and the 'M' key in the Watch Recordings page says that there are 201 recordings available somewhere, but they will not display. See screenshot:

(implicit thanks to whomever upvoted this, giving me sufficient reputation to upload images)

Changing the filter does not remedy the fact that there is nothing shown in the lists.

My Upcoming Recordings screen says that there are no rules set, but my list of previously recorded shows is still there, and has an entry from as recently as 3am today.

mythbackend --printsched gives the following:

user@box:~$ mythbackend --printsched
2012-09-22 12:59:20.537008 C  mythbackend version: fixes/0.25 [v0.25.2-15-g46cab93] www.mythtv.org
2012-09-22 12:59:20.537043 C  Qt version: compile: 4.8.1, runtime: 4.8.1
2012-09-22 12:59:20.537048 N  Enabled verbose msgs:  general
2012-09-22 12:59:20.537076 N  Setting Log Level to LOG_INFO
2012-09-22 12:59:20.537142 I  Added logging to the console
2012-09-22 12:59:20.537152 I  Added database logging to table logging
2012-09-22 12:59:20.537279 N  Setting up SIGHUP handler
2012-09-22 12:59:20.537373 N  Using runtime prefix = /usr
2012-09-22 12:59:20.537394 N  Using configuration directory = /home/user/.mythtv
2012-09-22 12:59:20.537999 I  Assumed character encoding: en_GB.UTF-8
2012-09-22 12:59:20.538599 N  Empty LocalHostName.
2012-09-22 12:59:20.538610 I  Using localhost value of box
2012-09-22 12:59:20.538792 I  Testing network connectivity to '192.168.1.2'
2012-09-22 12:59:20.539420 I  Starting process manager
2012-09-22 12:59:20.541412 I  Starting IO manager (read)
2012-09-22 12:59:20.541715 I  Starting IO manager (write)
2012-09-22 12:59:20.541836 I  Starting process signal handler
2012-09-22 12:59:20.684497 N  Setting QT default locale to EN_GB
2012-09-22 12:59:20.684694 I  Current locale EN_GB
2012-09-22 12:59:20.684813 N  Reading locale defaults from /usr/share/mythtv//locales/en_gb.xml
2012-09-22 12:59:20.697623 I  New static DB connectionDataDirectCon
2012-09-22 12:59:20.704769 I  MythCoreContext: Connecting to backend server: 192.168.1.2:6543 (try 1 of 1)
Calculating Schedule from database.
Inputs, Card IDs, and Conflict info may be invalid if you have multiple tuners.
2012-09-22 12:59:27.710538 E  MythSocket(21dfcd0:14): readStringList: Error, timed out after 7000 ms.
2012-09-22 12:59:27.710592 C  Protocol version check failure.
        The response to MYTH_PROTO_VERSION was empty.
        This happens when the backend is too busy to respond,
        or has deadlocked in due to bugs or hardware failure.

Things I have tried so far:

• restart the backend
• restart the frontend
• run mythtv-setup and check database passwords and IP addresses
• change the frontend setting for backend IP from localhost to 192.168.1.2 (the backend/frontend's IP)
• run optimize_mythdb.pl

Other suggestions appreciated.