Summary
A portable file (QBM) is a type of a Quickbooks company backup file, which is much more compressed than the regular Quickbooks Backup file (QBB).
Typically, it is used to have a compact version of your file for storing, or moving.
In some instances, a Portable file is needed to address some issues with large TLG files, which, under normal circumstances, are shrunk by performing a
backup with full verify. When a TLG file grows too large (over 1 - 1.5Gb), these types of backups start failing, and the way to shrink that log file is to make a portable backup, then restore it back on top of the live file to shrink the TLG.
Process
- Open your Company File in Question
- Go to File > Send Company File > Portable Company File

- Save the file to the backup folder. This would be: Q:\Backup\<Your Company File Name>\

This will close your company file and perform the backup.
Restoring the Portable Company File
If you are looking to restore the Company File back on top of your existing one to reduce the size of the TLG, you may do so by following these steps:
1- Close out of any open Company Files, and make sure no users are in the file you need to restore
2- Click on "Open or restore an existing company"

3- Select "Restore a portable file"
4- Browse to your portable backup file to restore, this will be in the last location you saved it: Q:\Backup\<Your Company File Folder>\
5- In the next step, browse to where you want to restore the file: Q:\Data\<Your Company File Folder>\<Your Company File Name.qbw>
6- You will get 2 warnings
When you click "Yes", you will see this warning

Typing YES in that dialog box will replace your previous company file with the restored version from the Portable Company file. Make sure this is what you want to do.

If you would like extra reassurance that your file is restorable to its previous state, please open a ticket with support, and request that a copy of your original file is set aside, in case they need to be reverted to.
Once the restore is complete, you are now ready to re-access your file.