This usually means Windows is set to allow apps only from Microsoft Store, not that the installer is unsafe.
Try this:
- Open Settings > Apps > Advanced app settings.
- Look for Choose where to get apps.
- If it appears, change it to Anywhere.
- Run the Bluebook installer again.
If Choose where to get apps does not appear, that commonly means the PC is in S mode.
To check:
- Press Start.
- Type winver and open it.
- Check whether Windows shows that it is running in S mode.
If the device is in S mode, switch out of S mode first, then try the installer again.
If the app still cannot be found or installed afterward, also try:
- Restart the PC, especially if Windows was recently updated.
- Reset Microsoft Store:
- Press Windows key + R
- Enter wsreset.exe
- Select OK
- Wait for the blank command window to close and Microsoft Store to open
- Confirm the app is available for the current country or region and compatible with the device.
References: