Please note, that before being able to use TM maintenance for a TM, the TM needs to be reorganized because of changes in its data structures. translate5 will do that automatically for a TM as soon as you start to try to use it in TM maintenance, yet with big TMs that will take some time and the UI might run into timeouts then. You can also migrate all TMs first on the CMD to the new format by using the command line interface. Go to the document-root of your translate5 installation dir in your php-docker-container and call there: t5 t5memory:reorganize The command has the following parameters --tmName=TMNAME If no UUID was given this will filter the list of all TMs if provided --batchSize=BATCHSIZE Number of memories to reorganize at once. Works only if no UUID and tmName was given --startFromId=STARTFROMID The IDs of the TMs you see when showing the “id” column in the language resource management in the UI.