Notes about the TCD file extension:
To open this file type, a required software must be installed. Without it you only see a Windows message "The following file cannot be opened
" (Windows 7) or "How do you want to open this file?
" (Windows 10) if you double-click the file. There click on "More apps"
and choose a suitable software to view such files on your PC or from email attachments.
The TCD file type is primarily associated with 'TopCopy' by Toplevel Computing. Extension is for documents read by the TopCopy word processor. TopCopy was the DOS precursor to Complete Works. Complete Works will read the .TCD file. The Complete Works product appears to no longer be offered or supported.