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Level: Powered On

Cannot update a Date field to an empty value?

I have a flow set up to update a SharePoint list, specifically to reset the status of all entries. However, in order to do that, I need to reset the date field to a blank value; attempting to do that gives the error 'String was not recognized as a valid DateTime.' Searching on the forum gives the suggestion that Numbers cannot be marked null; is it the same for DateTime fields?


For the record, the two calculations I'm using to reset date fields:

"@blank()" for the first

"@adddays(startofmonth(adddays(utcnow(),31)),-1,'yyyy-MM-dd')" to get the last day of the current month

Level: Powered On

Re: Cannot update a Date field to an empty value?

Is the column "required" in your list settings? Can you create a new form instead of trying to reset forms that have already been submitted?

Community Support Team
Community Support Team

Re: Cannot update a Date field to an empty value?

Hi @daniel_arm,


Can you please send us the detailed configuration of this flow? 




Community Support Team _ Mona Li
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.
Level: Powered On

Re: Cannot update a Date field to an empty value?


Frequency: Day

Interval: 1





If No, Do Nothing

If Yes:


Get Items


Apply to each

Select an output from previous steps: [sharepoint item] value


Sharepoint: Create Item


Sharepoint: Update Item

Site Address: [same as sharepoint item]

List Name: [same as sharepoint item]

*Id: [sharepoint item] ID

*Task: [sharepoint item] Task

Category: [sharepoint item] Category

Completed: No

Completion date: "@blank()"

Due Date: "@adddays(startofmonth(adddays(utcnow(),31)),-1,'yyyy-MM-dd')

Level: Powered On

Re: Cannot update a Date field to an empty value?

The specific error message that occurs when trying to run using this configuration is:

{ "Title": "Close out due MOCs", "Completed": false, "emvr": "@adddays(startofmonth(adddays(utcnow(),31)),-1,'yyyy-MM-dd')" }

String was not recognized as a valid DateTime.


This indicates to me that the cause of the error is a lack of interpretation of @ commands within the Update Items function; when I tried using the Create Items function, the calculated values are reflected in the new item, but it lacks the Person or Group field that is absolutely vital for usability.


At this point, I have attempted both routes I can think of to get this working in Flow; unless there are changes on the horizon, I will need to search out a separate piece of software to get this scheduled refresh working.

Level: Power Up

Re: Cannot update a Date field to an empty value?

click dynamic content, choose expression in popover dialog, in Fx box type null, click ok. this should set date to null

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