I have a MacBook 7.2 with Linux (Arch) and MacOSX dualboot.

Software is
KDE: 4.8.2
Strigi: 0.7.7
dbus: 1.4.20
QT: 4.8.1

Most of the times, I get an error of the Nepomuk/Strigi system,
http://cloud.brain-frog.de/apps/files_s ... 4c93b0a5ae

I reinstalled X, KDE, QT, dbus and cleaned out the home dir. After this file indexing worked for one day / boot cycle. Now the error is back. Any hint?

This indicates that part of Nepomuk likely crashed, possibly repeatedly. Alternately, it could be hung.
Do you have any log files of this?

Right now it works. Anyways, I post you what I found in .xsession-errors Which other logs might be interesting?

Right after the system started with Nepomuk Desktop File Indexing _disabled_
[/usr/bin/nepomukservicestub] virtual void Soprano::Server::ServerConnection::run() thread done.
[/usr/bin/nepomukservicestub] virtual Soprano::ODBC::Connection::~Connection() Soprano::Server::ServerConnection(0xb2d8b0)
[/usr/bin/nepomukservicestub] void Soprano::Server::ServerCore::serverConnectionFinished()
virtual Soprano::Server::ServerConnection::~ServerConnection() Removing connection
[/usr/bin/nepomukservicestub] void Soprano::Server::ServerCore::serverConnectionFinished() Connection removed. Current count: 6

After starting indexing the File indexing but not the email indexing
[/usr/bin/nepomukservicestub] virtual void Soprano::Server::LocalServer::incomingConnection(quintptr)
[/usr/bin/nepomukservicestub] void Soprano::Server::ServerCorePrivate::addConnection(Soprano::Server::ServerConnection*) New connection. New count: 7
[/usr/bin/nepomukservicestub] Soprano::ODBC::Connection::Connection() Soprano::Server::ServerConnection(0xb2dff0)
[/usr/bin/nepomukservicestub] virtual void Soprano::Server::LocalServer::incomingConnection(quintptr)
[/usr/bin/nepomukservicestub] void Soprano::Server::ServerCorePrivate::addConnection(Soprano::Server::ServerConnection*) New connection. New count: 8
[/usr/bin/nepomukservicestub] Soprano::ODBC::Connection::Connection() Soprano::Server::ServerConnection(0xb7dc40)
plasma-desktop(1044)/plasma StatusNotifierItemSource::refreshCallback: DBusMenu disabled for this application
[/usr/bin/nepomukservicestub] Soprano::ODBC::Connection::Connection() QThread(0xb897e0, name = "Thread (pooled)")
plasma-desktop(1044)/plasma StatusNotifierItemSource::refreshCallback: DBusMenu disabled for this application

While strigi is indexing now I see a lot of error messages in .xsession-errors of this kind.

"/usr/bin/nepomukservicestub(1089)" Soprano: "SQLExecDirect failed on query 'sparql select ?r where { ?r <http://www.semanticdesktop.org/ontologies/2007/01/19/nie#url> <file:///home/killmann/NonlinearDynamics/kra_rose_pik/shorts25000_a5_23.mat> . } limit 1' (iODBC Error: [OpenLink][Virtuoso iODBC Driver]CL064: Lost connection to server)"
"/usr/bin/nepomukservicestub(1089)" Soprano: "Invalid iterator."

Now there is a bug report.

The first set of messages are innocuous, the second one is definitely bug report material, which I see has been done.