Copilot Studio to Power Automate – file input error (UnspecifiedDataType type mismatch)

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Posted on by CU26070553-0

Hi,

I'm trying to send an uploaded Excel file (`.xlsx`) from Copilot Studio to a Power Automate(Agent) flow. The flow expects a file parameter, but I get the following error:

Here is my Error Message

The flow ‘My Flow Name’ (Flow ID) failed because the parameter named file was declared with type UnspecifiedDataType. This type is not supported when invoking Power Automate. Currently, only Text, Boolean, and Number types are supported.

Error code: FlowActionBadRequest.

Conversation ID: ConverSationID

Timestamp (UTC): 7/26/2025 5:41:02 AM

I attached Two images

First image is Copilot Studio's topic and the excel's filetype is "Record".

And the second image is Agent flow

the agent flow's excel file type is "File"

How can I Integrate this file type ?

Expected:

I want to send a file from Copilot Studio that Power Automate can recognize and process properly — preferably as an attachment or stream.

Is there any workaround, or planned support for passing file-type parameters from Copilot Studio to Power Automate(Agent Flow)?

Categories:

Flow Integration

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Michael E. Gernaey 47,123 Super User 2025 Season 2 on at

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Copilot Studio to Power Automate – file input error (UnspecifiedDataType type mismatch)

Hi @CU26070553-0

Ahh here is a sample i just created for you

When you initially create your flow, you will Send a Question to have them upload a file.

Now while it is saved as a File, I prefer not to use the specific Variable beyond this, but you can, I won't.

Now I want to call my Agent flow, which takes in a File Content (record)

Now i go back to my Topic and I add in the Call to the Agent Flow. Whether you are calling an Agent Flow, or a Specific Flow you built and are leveraging it the same. Select the File Content input. I changed the name to UserFile.

Now in my Topic I update my call details like this

for the UserFile (record) , I add the input value as a JSON record like so

{

contentBytes:

First(System.Activity.Attachments).Value,

name:

First(System.Activity.Attachments).Name

}

Where in the UI it looks like this

And then I just send a message back that says I saved it.

To test, I trigger my topic by typing Hello

I click the Attach File Paperclip, pick my file and hit send and bingo it works

Oh and in my Flow i use the variables like this

Where my URL Site I left out

And in the flow it wont be called Value. it will be the dynamic properties of the UserFile input

so click / on the line and select UserFile name and then / and UserFile content

If these suggestions help resolve your issue, Please consider Marking the answer as such and also maybe a like.

Thank you!
Sincerely, Michael Gernaey

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Michael E. Gernaey 47,123 Super User 2025 Season 2 on at

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Copilot Studio to Power Automate – file input error (UnspecifiedDataType type mismatch)

Hi @CU26070553-0

Any updates here or feedback on my solution?

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Michael E. Gernaey 47,123 Super User 2025 Season 2 on at

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Copilot Studio to Power Automate – file input error (UnspecifiedDataType type mismatch)

Hi @CU26070553-0

Just as feedback, when you say something doesn't work but do not share anything at all, it is super difficult to help as you could have a dozen issues.

But please follow this.

Copilot Studio Easiest Way To Upload A File In A Chat Window

There are changes now based on Attachments and Record changes in Copilot, which was retrofitted into this example.

If these suggestions help resolve your issue, Please consider Marking the answer as such and also maybe a like.

Thank you!
Sincerely, Michael Gernaey

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