Before offering to db, I put debug printing: qDebug() << "db.drivers()=" << db.drivers(); It gives correct list of drivers on the development platform and empty set on deployment platform. if (db.isDriverAvailable("QODBC")) db = QSqlDatabase::addDatabase("QODBC"); //It is a fragment of code for opening mdb (str is a full name to file from file-open dialog): if (db.isOpen()) db.close(); qDebug() << "db.drivers()=" << db.drivers(); db.setDatabaseName("DRIVER={Microsoft Access Driver (*.mdb)};FIL={MS Access};DBQ="+str+"; Uid=Admin; Pwd=; ExtendedAnsiSQL=1;"); bool ok = db.open(); if (ok) { // processing with sql }