The NET HELPMSG command will decode Windows error codes, at least the simple ones

A quick and dirty way to convert Windows error codes to strings is to use the NET HELPMSG command.

C:\> NET HELPMSG 2

The system cannot find the file specified.

C:\> NET HELPMSG 8242

An invalid dn syntax has been specified.

The command is not infallible, however.

• It operates only on Windows error codes. It doesn't decode HRESULT or NTSTATUS values.
• It doesn't support messages with insertions, presumably because it doesn't pass the FORMAT_MESSAGE_IGNORE_INSERTS flag.

If you pass a message with an insertion, such as ERROR_WRONG_DISK, then instead of getting

The wrong diskette is in the drive.
Insert %2 (Volume Serial Number: %3) into drive %1.

you get¹

C:\> NET HELPMSG 34

34 is not a valid Windows network message number.

More help is available by typing NET HELPMSG 3871.

Still, it's better than nothing.

¹ As a bonus insult, if you type the suggested command, you get this:

C:\> NET HELPMSG 3871

*** is not a valid Windows network message number.

Yeah, um, that really didn't tell me anything new.