Cant Change Tempo, and whats the feature "ext"?

[Jonatan King]

I was working on a project a few weeks ago. Today, I decided to reopen it and wanted to listen to a section at a slower tempo to verify drum rhythms.

When I try to change the tempo, the box appears grayed out and won't let me change it. There's also a new option on the left called "Ext" that I don't know what it does.

When I click on "Ext", it enables the tempo box for me to change, but it doesn't let me play anything in the project. This is new since I use Ableton at least 11 hours a day, and this option only just appeared.

How can I fix this?

[Tarekith]

When you click on the Ext button you are telling Live to have its tempo set from external midi sources, that’s why you can no longer change it in Live. Deselect the MIDI input sync option in the midi preferences to get rid of that button.