We will need to decrypt it back to Install.wim, so that it can be used on a Windows to Go drive.
Let's get started
1. Create a virtual machine, you can either use Oracle's VirtualBox or Windows 8.1 Pro's build in Hyper-V, make sure the virtual HDD is set as VHD or VHDX
2. Install Windows 8.1 into the virtual machine

3. Sysprep Windows 8.1

4. Attach the virtual drive in Disk Management and note the virtual drive's letter that has the largest partition

5. Capture it with ImageX, from virtual drive to C:\
Note, the command prompt screen will black out for some time up, just wait

6. ImageX is creating Install.wim

7. When it's done, the Install.wim will be located in the C:\
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