What's the largest REG_SZ value that Regedit can edit?

Question

I came across a large string value (REG_SZ) in the Registry and I want to copy it. As I double clicked the value, the textbox was empty.

What is the largest REG_SZ value that Regedit can edit in its textbox?

Answer 1

The largest string that can be displayed in the Regedit's textbox has a length of 43679. beginning with a length of 43680, the textbox will appear to be empty. (Windows 10 21H1, if that matters).

And I say "appear", because the value is actually still there. You can press Ctrl+A and Ctrl+C in order to copy it into the clipboard. And you can also copy a text into the clipboard and paste it back to Regedit and accept it.

Answer 2

I am sure Ctrl + A & Ctrl + V will not always work, since it does not work on this two keys:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsSelfHost\OneSettings\TargetingAttributes
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsSelfHost\OneSettings\TargetingAttributesVerified

Both values are multi-line very long texts (>60000 each), just like this small reduced sample pattern:

{
  "Version": ...
  "SchemaVersion": ...
  ...
}

But i can confirm that Ctrl + A & Ctrl + C works, it copy the very long multi-line value perfectly.

But any attempt to put a new multi-line value (for a simple edit of a small part) does not work, no matter how long or short it is, it will only take/accept (write) the first line of the text.

So using REGEDIT to edit such kind of values looks like it is not an option.

Also tried:

• If i export the branch to a (.reg) file, edit the text inside the (.reg) file and try to re-import (double clicking) and refresh (with F5 key), such values are not updated.
• If i export the branch to a (.reg) file, delete the key, try to re-import (double clicking) and refresh (with F5 key), such keys are not imported (but the message says all keys were imported).
• I also had tested with a short multi-line value, same results, no way to paste it, only accepted first line, also ignored if inside a (.reg) file, etc.

The key type is somehow weird, it is REG_SZ, not REG_MULTI_SZ.

That is getting me really madness, how is it possible to put/edit such values when they are multi-line in a REG_SZ type key is something i do not know.

Thanks anyway, at least i can read/copy them.