Notes about the 3DT file extension:
Incorrect file associations could be the result of underlying issues within your PC system. As such it is highly recommended to scan your PC for invalid registry entries
, unused processes and other unfavourable system settings to identify slowdown issues.
The 3DT file type is primarily associated with '3D Greetings' by Riverdeep Interactive Learning Limited.
3D Greetings is included with different Broderbund products and us used in conjunction with them to produce greeting cards.
There is a US-CERT Vulnerability notice on one of the 3D Greetings versions. See the affiliated links.