To save only the existing share names and their permissions on Windows follow these steps.
Note
This procedure applies only to NetBIOS shares and not to Macintosh volumes.
On the existing Windows installation that contains the share names and permissions that you want to save, start Registry Editor (Regedt32.exe).
From the HKEY_LOCAL_MACHINE subtree, go to the following key:
SYSTEM\CurrentControlSet\Services\LanmanServer\Shares.
Save or export the registry key.
For Windows NT and Windows 2000, click Save Key on the Registry menu.
For Windows Server 2003, click Export on the File menu.
Type a new file name (a file extension is not necessary), and then save the file to a floppy disk.
Reinstall Windows.
Run Registry Editor (Regedt32.exe).
From the HKEY_LOCAL_MACHINE subtree, go to the following key:
SYSTEM\CurrentControlSet\Services\LanmanServer\Shares.
Restore or import the registry key.
For Windows NT and Windows 2000, click Restore on the Registry menu.
For Windows Server 2003, click Import on the File menu.
Type the path and file name of the file that you saved in steps 3 and 4.
Caution
This step overrides the shares that already exist on the Windows computer with the share names and permissions that exist in the file you are restoring. You are warned about this before you restore the key.
Restart the server.
Note
After you complete this procedure, if you decide that you should not have restored the Shares key, restart the computer and press the SPACEBAR to use the last known good configuration. After you restore the shares key, the shares can be used by network clients. If you run the net shares command on the server, the server displays the shares; however, File Manager does not display the shares. To make File Manager aware of the newly restored shares, create any new share on the server. File Manager displays all of the other shares after you restart the server or stop and restart the Server service.
In Windows NT 3.5, if you click Stop Sharing in File Manager, the restored shares are still displayed, but they are dimmed.
Only permissions for domain users are restored. If a local user was created in the previous Windows NT installation, that local user's unique security identifier (SID) is lost. NTFS permissions on folders and files are not affected when you save and restore the shares key.
Saving and restoring existing Windows shares - Windows Client | Microsoft Learn
