```
bitcoind -par=1
```

Excerpt from the `debug.log`:

```
Using 0 threads for script verification
```

Zero? I guess not ;)
{
    
    fs::path datadir = GetDataDir();
    if (!DirIsWritable(datadir)) {
        return InitError(strprintf(_("Cannot write to data directory '%s'; check permissions.").translated, datadir.string()));
    }
    if (!LockDirectory(datadir, ".lock", probeOnly)) {
        return InitError(strprintf(_("Cannot obtain a lock on data directory %s. %s is probably already running.").translated, datadir.string(), PACKAGE_NAME));
    }
    return true;
}
bool AppInitSanityChecks()