How to backup and restore registry using only win10 iso command prompt

In a link it suggested several registry troubleshooting steps for a Windows with black screen.

For Windows 10 1909 how do you backup and restore one registry change using a windows 10 iso command prompt?

If more than one registry entry is modified how do you backup and restore a second change?

In addition to modifying one or two commands how do you backup and restore the whole registry when the only access is via a windows 10 iso command prompt?

I'm not sure about your question but Reg command can be use to backup registry.

Code:

REG EXPORT HKLM\Software\MyCo\MyApp AppBkUp.reg

If a computer is booted using a Windows 10 iso 1909 > troubleshoot > command prompt > regedit
(not yet used regedit in Windows RE commnd prompt)

HKEY local machine > software > Microsoft > Active setup > Installed components > etc.
If an entry is delted how is it recovered?

What do you do to backup the current entry?
What do you do to restore the entry?

Do you repeat the steps for each entry deletion or change?

How do make a backup of the whole registry and then restore the whole registry using only Windows RE command prompt?

This is a double backup?
(both a single backup and the whole registry backup?

And how do you restore each of the different types of backups using only Windows RE command prompt?
(I rarely ever have reason to modify the registry but may need to fix recent Windows upgrade problems)

To back up the hives:

cmd prompt type:
notepad
when notepad pops up click File>Save

Use the save dialog to browse to hard disk windows system32\config rt click the config folder and copy - then paste it somewhere else - e.g. into a new folder you have created.

Alternatively, just copy the hives and paste them back into config folder - don't overwrite the existing ones.

If you want to make occasional hive backups from within windows, regbak is a handy free program
Acelogix Software - Registry Backup and Defrag (Freeware)

The only access post windows upgrade is Windows RE using a windows 10 iso.

Registry steps may be needed that require deletion of the registry entries.

Aren't there two methods for backup: a single change and the whole registry?
I've never done either and need specific steps using Windows RE command prompt.
Also I've never restored a registry backup.
How do you restore a single backup using Windows RE command prompt?
And how do you restore the whole backup?

Again I've never done any significant changes in the registry and need specific steps using only the Windows 10 iso.

GUI mode:		REGEDIT.EXE
Import (merge) a .REG file:		REGEDIT.EXE [ /L:system | /R:user ] [ /S ] importfile.REG
Export to a (.REG) file:		REGEDIT.EXE [ /L:system | /R:user ] /E exportfile.REG "registry_key"
Compress the registry (Windows 98 only):		REGEDIT.EXE [ /L:system | /R:user ] /C

When you Load Hive you will assign temporary Hive name when you backup loaded hive it will have this temporary hive name (HKEY_LOCAL_MACHINE\Temp) as you can see Temp is the temporary Hive name for Software hive i have loaded. So when restoring backup of this Software hive load the Software hive again with same temporary name (Temp).

I just explained how to back up the hives from command prompt in winre. Do that before making any changes to the originals.
You can restore them in the same way - copy and paste using notepad save as dialog.


HIves can be edited by opening regedit. At winre cmd prompt type: regedit

Click on HKEY_LOCAL_MACHINE (HKLM) to highlight it, then click Load hive - navigate to the hive on your windows partition and pick it up. Give it any name you like. For example C_soft

Then you will see C_soft under HKLM and you make any changes/export exactly the same as you do in windows..




If you export anything, the path in the exported reg file will show C_soft, obviously.

example:

Code:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\C_soft\7-Zip]
"Path32"="C:\\Program Files\\7-Zip\\"
"Path"="C:\\Program Files\\7-Zip\\"

Then make sure the loaded C_soft hive is highlighted and click Unload Hive.

zbook said:

The only access post windows upgrade is Windows RE using a windows 10 iso.

Registry steps may be needed that require deletion of the registry entries.

Aren't there two methods for backup: a single change and the whole registry?
I've never done either and need specific steps using Windows RE command prompt.
Also I've never restored a registry backup.
How do you restore a single backup using Windows RE command prompt?
And how do you restore the whole backup?

Again I've never done any significant changes in the registry and need specific steps using only the Windows 10 iso.