Old signature being used

I have updated my New and Reply signatures since my company changed names. Everything works fine when emails are HTML format,
but when I Reply or Forward a Plain Text email, my OLD SIGNATURE is applied. I don’t even see the old signature in the Signature Options!
Where can I access this phantom signature and update it?

There are 3 signatures templates per signature; one for each format;

• Plain Text-> .txt
• HTML-> .htm
• Rich Text-> .rtf

Normally when you update your signature via the Signature Editor (Tools-> Options-> tab Mail Format-> Signatures…), all 3 signature files are automatically updated. Under certain conditions, this is not the case. In those cases you’ll have to manually edit the formats that didn’t change automatically.

To easily open the Signatures folder to access the 3 files, you can hold the CTRL button on your keyboard while clicking the Signatures… button. If this doesn’t work for you, you can find the Signatures folder here;

Windows Vista
C:\Users\%username%\AppData\Roaming\Microsoft\Signatures

Windows XP
C:\Documents and Settings\%username%\Application Data\Microsoft\Signatures

Note: If you made a lot of changes to the signature, you can also opt to delete the files that didn’t got updated and then save the signature again in the Signature Editor (add and remove a space if the Save button is not accessible to you). The missing files should be recreated now again. Another way to go would be to copy the contents to a new signature.

To find out more about using Signatures in Outlook see this guide.