I am working on some macros to automate charting and am having trouble with
the column that contains the times (x values).

In particular, the column is formatted as type "Custom hh:mm" and so I
simply tried the following:

strDateStart = ActiveCell.Value

which returns a decimal time. I have tried applying the TimeValue function
to the cell contents

strDateStart = TimeValue(ActiveCell.Value)

but it gives me a type mismatch error.

Could anyone please shed any light on this.

Thanks a lot

P.S. The Excel spreadsheet has been itself auto-generated via a third party
Delphi application. So I cannot control the original format of the source
data.