Restoring an old bkf backup file on macOS or Windows 10 (/8/7)

I recently realised I had a load of old projects and data sitting in a lovely 100GB bkf file – generated by the ntbackup program that used to ship with Windows XP and Windows 2008 – but no way to access them.

Microsoft released a restore-only version for 2008 R2 / Windows 7, but there was no version of ntbackup I could find that would run on Windows 10.

There were loads of blog and StackExchange posts but generally pointing to dodgy (and since dead) downloads of ntbackup.exe. I could install Windows XP on a VM, or launch a Windows 2008 R2 instance in Azure/AWS and transfer the files up there, but those felt like a lot of hassle.

Fortunately I found a C based utility on GitHub called mtftar which converts an MTF stream into a TAR based stream, and someone has generously updated it to compile on both Windows and macOS. Great!

I have Ubuntu running under the Windows subsystem for Linux, so with build-essential already installed via apt-get, I ran:

> git clone https://github.com/sjmurdoch/mtftar
> cd mtftar
> make
> ./mtftar -?

Which lists out the various supported command line arguments. I went for

./mtftar < Backup.bkf | tar xvf -

which extracted the bkf archive straight onto the file system in the same directory. The same commands work on macOS, if you prefer to run there.