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"SubtractDate must be Datetime" error in Power Automate Desktop when using datetime variable

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Posted on by 美近-19060449-0

I am creating a flow in Power Automate Desktop (version 2.57.184.25154) to retrieve the datetime one month prior to the current date.

For example:

If the current month is 202506, I want to get 202505.

I used the "Get current date and time" action to generate a datetime-type variable,

and passed it to the "Subtract dates" action.

However, the following error is displayed:

Error message:

The argument 'SubtractDate' must be of type 'Datetime'.

The variable is recognized as a Datetime value, and I believe its type is correct.

I have tried:

Renaming the variable

Restarting Power Automate Desktop

Reinstalling the application

But the same error continues to occur.

Below is the structure of the flow:

Get current date and time → %現在日時_raw%

Subtract dates → %現在日時_raw% minus 31 days → %前月日時%

I would appreciate it if you could provide any possible causes or similar known issues.

Categories:

Power Automate Desktop

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eetuRobo 4,484 Super User 2026 Season 1 on at

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Subtract dates -action expects two dates.

I assume you are giving it one date (From date) and number of days to substract (Subtract date) which seems to be -31 in your flow:

Use "Add to datetime" -action instead. Even though the actions says "Add to datetime" you can substract by giving negative number to the "Add" -field

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VishnuReddy1997 2,656 Super User 2026 Season 1 on at

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Hi @美近-19060449-0,

Please find the solution. Please copy the below code to your flow.

Code:

DateTime.GetCurrentDateTime.Local DateTimeFormat: DateTime.DateTimeFormat.DateAndTime CurrentDateTime=> CurrentDateTime DateTime.Add DateTime: CurrentDateTime TimeToAdd: -1 TimeUnit: DateTime.TimeUnit.Months ResultedDate=> ResultedDate Text.ConvertDateTimeToText.FromCustomDateTime DateTime: ResultedDate CustomFormat: $'''yyyyMM''' Result=> FormattedDateTime

(Note:- if you got your solution you can mark as solution and gives kudos)

Thanks & Regards
Vishnu Reddy

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美近-19060449-0 9 on at

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VishnuReddy1997

Thank you so much! Your explanation and sample flow worked perfectly. I was stuck for days, but now it's finally working thanks to you. Really appreciate it!

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美近-19060449-0 9 on at

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eetuRobo
Now I understand that I should have used the "Add to datetime" action in this case.
The issue is resolved. Thank you so much for your clear and helpful response!

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