You're the man. Total, complete, fantastic success!

Thank you so much!

-Rich

Very close to the final solution now!

My Y axis is now showing the appropriate "mm:ss" format and in the correct interval. In vertical axis properties I have a custom number...

Yeah basically totally unformatted the values go from 0 to 130 seconds and display as those numbers at intervals of 10. All I want to do is literally just change...

Been tinkering with your solution. In my y-axis number formatting I have a custom format set as:

=Format(TimeSerial(0,0,Fields!SecondsValue.Value), "mm:ss")

Still giving me the same result though.

00:50

00:60

00:70

instead of

00:50

01:00

01:10

Frustrating 🙂