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ZLJ Regular Visitor
Regular Visitor

Not a legal OleAut date

Has anything changed in Power BI in the last week?  I have a few Datasets / Reports which are no longer refreshing in Service due to the error "Not a legal OleAut date".  I've narrowed it down to some bad dates in one column (i.e. 11/09/0212).  However, these reports were running fine last week, and the source data has not changed (it has always been bad).  They also work in Desktop, it is just the schedule refresh in Service that is a problem.  


I want to understand what has changed or why they are failing now, rather than just write a formula to replace the bad values.  




Moderator v-yuezhe-msft

Re: Not a legal OleAut date

Hi @ZLJ,

You can check this article for known issues and recently-released  updates in Power BI Service. However, Power BI team hasn’t release any Power BI Service updates of July in the official articles, we need to wait a period of time.

In addition, as far as I know, several persons have encountered the same error message by using schedule refresh option in Power BI Service, and the root cause is that there are incorrect date values in data source. In your scenario, you will need to correct these illegal data values to make schedule refresh work properly.

There is a similar thread for your reference.

Lydia Zhang

Community Support Team _ Lydia Zhang
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.
ZLJ Regular Visitor
Regular Visitor

Re: Not a legal OleAut date

Thanks @v-yuezhe-msft

I fixed the dates in the source data, and it started to run again.  However, that still doesnt explain why it ran for a few weeks previously with no issues?  I checked the source data, and the bad dates had been there for years, they werent a new thing.  I'm worried that other reports could stop working with no warning for similar reasons in the future.  Would there be any reason why a bad date would work on a schedule refresh one week, and then start to error?  Is there a min / max date that is allowed in Power BI?  

umutgulac Frequent Visitor
Frequent Visitor

Re: Not a legal OleAut date

I have the same problem and it was used to work fine.


What happened and it started to return error about dates.

In my database, there are many date fields and I am not sure what date is an inappropriate date, "0000-00-00 00:00:00" is iniappropriate? Power BI gets them like they are null, so this should not be problem?


What is the exact root cause of this error?

Hamlet Frequent Visitor
Frequent Visitor

Re: Not a legal OleAut date

Hey guys!


Same issue here, in particular with the function:


FechasDax = 
VAR BaseCalendar = 
        VAR BaseDate = [Date]
        VAR YearDate = Year(BaseDate)
        VAR MonthNumber = Month(BaseDate)
        RETURN ROW(
            "Day", BaseDate, 
            "Year", YearDate,
            "Month Number", MonthNumber,
            "Month", FORMAT(BaseDate,"mmmm"),
            "Month Year", FORMAT(BaseDate,"mmm yy")

Any suggest? Thanks!