Arithmetic overflow error when using sp_Blitz
There was an issue with the latest release, shown in ISSUE 526. It was updated, by changing this code on line 472. 

FROM

SELECT @MsSinceWaitsCleared = 
DATEDIFF(MINUTE, create_date, CURRENT_TIMESTAMP) * 60000


TO 

SELECT @MsSinceWaitsCleared = 
DATEDIFF(MINUTE, create_date, CURRENT_TIMESTAMP) * 60000.0


If you do a new Pull request through github it has the fix in it.