Why did William windom who played dr seth haslett on murder she wrote leave before the last episode?

William Windom, who played Dr. Seth Hazlitt on Murder, She Wrote, did not leave the show before the last episode. He actually appeared in the very last episode of the series, titled "The Last Free Man."

However, he did leave the show for a period of time after the show's 8th season. The reason for his departure was due to a scheduling conflict with another television series he was filming. He returned to the show in the 9th season and remained a regular until the end of the series.

So, while there was a temporary departure during the show's run, William Windom was indeed present in the final episode of Murder, She Wrote.