Hi again everyone....

I am currently using the following custom format:

[h]:mm

How can I use data validation to prevent invalid
data from being entered into a cell of that format??

For my purposes, I only want data which consists
of 1 or more digits in the "hours" field, folowed by
one colon, followed by 1 to 2 digits in the minutes
field.

Do I need to enter some sort of formula into the
data validation field??

thank you!