Here’s some feedback on the test build referenced above.
Background: I’ve used Boxcrypter with Google Backup and Sync for a few years. I’ve just bought a new laptop on which I’ve installed Google Drive for desktop (because Google Backup and Sync is no longer readily available for new installation).
When I use Google Drive for desktop in “Stream” mode, I found that there is a problem when I try to open an encrypted file on my new laptop via the Boxcrypter drive: the application (in this specific case LibreOffice) reports the file is corrupt. I can close the file, wait a few seconds, and try again, and then it opens the file OK. This problem is NOT fixed by the test build of Boxcrypter (2.48.1852). I had no problems opening unencrypted files.
When I use Google Drive for desktop in “Mirror” mode, I found that with the released version of Boxcrypter (2.47.1752), Boxcrypter did not automatically recognise the Google Drive (i.e. there was no “Google Drive” virtual folder in the Boxcrypter drive after installing Boxcrypter). This problem WAS fixed by the test build of Boxcrypter.
Based on the experience described above, I am using Google Drive for desktop in Mirror mode and the test build of Boxcrypter on my new laptop, and so far it’s working OK. I hope this is useful to someone!