What happened to the Star Trek Online Foundry?

The Star Trek Online Foundry was a PC tool for creating and sharing player-made missions. Cryptic retired it on 11 April 2019.

Direct Answer

When was the Star Trek Online Foundry removed?

It was removed from the PC version during maintenance on 11 April 2019.

Foundry shutdown

11 April 2019PC · RETIRED

The Foundry let PC players create and publish their own playable STO missions using maps, dialogue, objectives, NPCs and encounters.

For the full shutdown announcement or historical editor details, use these two sources.

Official announcement

Cryptic's shutdown announcement, including its stated reasons for retiring the system.