First-chance exception at 0x005532a7 (QtLocationd1.dll) Access violation reading location 0x0000004f.

QSize QGeoTiledMappingManagerEngine::tileSize() const
{
Q_D(const QGeoTiledMappingManagerEngine);
return d->tileSize;
}

When the program with QTLocation runs a while ( for example, several hours), the pointer d becomes an invalid pointer.

Please find the text file for the call stack.

Thanks.