SharePoint Create File in Power Automate: 13 Tested Behaviors

SharePoint Create file in Power Automate is the action that uploads a file to a document library. It needs four values: Site Address, Folder Path, File Name, and File Content, for example concat('daily-report-', formatDateTime(utcNow(), 'yyyy-MM-dd'), '.txt') as the name.

That part is easy. What the action does with duplicates, odd characters, and missing folders isn’t documented well, so I built a test flow with 13 Create file checks and one metadata update, ran it, and opened every file in SharePoint.

How Do You Use the SharePoint Create File Action?

Add the action from the SharePoint connector and fill in its four required fields. Here’s what each one expects in the new designer:

1. Site Address: pick your site from the list, such as https://contoso.sharepoint.com/sites/finance.
2. Folder Path: browse to a library or folder. It must start with an existing library, like /Shared Documents/Reports.
3. File Name: type a name with its extension, or build one with an expression.
4. File Content: plain text, binary output from another action, or decoded base64.

The most common real use is saving files that arrive by email. I walk through that full build in my guide on how to save email attachments to SharePoint with Power Automate.

What Happened in My 13 Create File Tests?

Every action ran in parallel after a manual trigger, so one failure couldn’t hide the others. Then I checked the real file names, sizes, and contents in the library.

Test	Input	Result in SharePoint
Plain text content	Hello from Power Automate	Saved as written, 25 bytes
Base64 decoded	base64ToBinary('SGVsbG8gZnJvbSBiYXNlNjQ=')	File reads “Hello from base64”
Base64 not decoded	SGVsbG8gZnJvbSBiYXNlNjQ=	File holds the base64 text itself
Date in the name	daily-report- + formatDateTime(utcNow(), 'yyyy-MM-dd')	daily-report-2026-10-13.txt
GUID in the name	concat(guid(), '-invoice.txt')	Unique name, no conflict
Colon in the name	Invoice: October.txt	Saved as Invoice_ October.txt
Question mark in the name	report?.txt	Saved as report_.txt
Hash and percent	Q4 #1 100%.txt	Saved as Q4 #1 100%25.txt
No extension	README	Saved, but with no file type
Missing nested folders	/Create File Tests/2026/October	Both folders created
Library doesn’t exist	/No Such Library	Failed: BadRequest, Root folder is not found
Same name, first save	overwrite-test.txt	Created, version 1.0
Same name, second save	overwrite-test.txt	Overwritten, version 2.0

Three of those results surprised me: the silent overwrite, the swapped characters, and the %25. The sections below explain each one and how to handle it. If you’re new to actions and expressions, start with my Power Automate tutorials hub.

Does Create File Overwrite an Existing File?

Yes. When I saved overwrite-test.txt twice, both actions succeeded. The file held the second text, and its version changed to 2.0. There’s no error and no warning in the run.

The older content stays in version history, but most users never look there. If two people email invoice.pdf on the same day, the second file replaces the first one.

The fix is a unique name. A timestamp keeps names readable, and the formatDateTime() function gives you the exact format:

concat(formatDateTime(utcNow(), 'yyyyMMdd-HHmmss'), '-', 'invoice.pdf')

If several files can arrive in the same second, use guid() instead. It’s ugly, but it can’t collide:

concat(guid(), '-invoice.pdf')

What Happens to Invalid Characters in the File Name?

SharePoint doesn’t reject them. In my run, Invoice: October.txt became Invoice_ October.txt and report?.txt became report_.txt. The colon and question mark were replaced with underscores.

That sounds helpful, but it breaks later steps. If another action looks for report?.txt, it won’t find report_.txt. So clean the name yourself before Create file, and you’ll know the exact result.

Microsoft lists these characters as not allowed in SharePoint and OneDrive names: " * : < > ? / \ |. Leading and trailing spaces aren’t allowed either. Here’s a replace() chain for the common ones in subject lines:

replace(replace(replace(trim(triggerOutputs()?['body/subject']), ':', '-'), '?', ''), '/', '-')

Before you clean a value, make sure it isn’t blank. My guide on the Power Automate condition if blank shows a safe check.

Why Does a Percent Sign Turn Into %25?

Because the name was URL-encoded once and never decoded. I sent Q4 #1 100%.txt, and the library shows Q4 #1 100%25.txt. The # stayed as typed.

Users will see that odd name in SharePoint, and links built from the original name won’t match. The simple fix is to replace the percent sign with a word before saving:

replace('Q4 #1 100%.txt', '%', ' percent')

Do You Need to Create the Folder First?

No, only the library has to exist. My path /Shared Documents/Create File Tests/2026/October pointed at two folders that weren’t there, and Create file built both of them.

That makes date-based folders a one-step job. This expression creates a folder for each year and month:

concat('/Shared Documents/Reports/', formatDateTime(utcNow(), 'yyyy'), '/', formatDateTime(utcNow(), 'MMMM'))

A wrong library is different. The path /No Such Library failed with BadRequest and the message “Root folder is not found.” Pick the library from the folder browser to avoid typos. To reuse the date in several steps, set a variable to today’s date first.

What Should Go in the File Content Field?

Whatever bytes you want in the file. Plain text works as is: I typed Hello from Power Automate and got a 25-byte text file with exactly that line.

Base64 is where people get stuck. If you paste a base64 string, SharePoint saves the string itself, not the decoded file. My base64-not-decoded.txt contained the raw 24 characters.

Wrap it in base64ToBinary() to save the real content:

base64ToBinary('SGVsbG8gZnJvbSBiYXNlNjQ=')

You don’t need that for Outlook attachments, though. The contentBytes value from the Outlook trigger produced a byte-perfect PDF in my email test.

How Do You Set Columns After Create File?

Create file only uploads the file. To fill library columns, add Update file properties right after it and set Id to the ItemId output of Create file:

outputs('Create_file')?['body/ItemId']

In my test, this set the Title column to “Note created by Power Automate”. Notice that it also bumped the file to version 2.0, because SharePoint counts a metadata change as a new version.

Don’t use the Id output for this field. That value is an encoded file path, not the list item number Update file properties expects.

You can also stop a flow before it runs if the incoming data doesn’t qualify, using Power Automate trigger conditions.

SharePoint Create File Cheat Sheet

Every row below matches a result from my test run.

Need	What to use
Avoid silent overwrites	concat(guid(), '-', 'file.pdf')
Readable unique name	concat(formatDateTime(utcNow(), 'yyyyMMdd-HHmmss'), '-', 'file.pdf')
Folder per month	Put the year and month in Folder Path; missing folders are created
Decode base64 text	base64ToBinary(x)
Remove invalid characters	replace() for : ? / \ * " < > |
Avoid %25 in names	replace(x, '%', ' percent')
Set library columns	Update file properties with Id = ItemId

Frequently Asked Questions

More Power Automate Tutorials

Once your files are landing where they should, these are worth a look next:

• adding days to a date with addDays()
• converting a string to an integer
• Power Apps vs Power Automate: when to use each
• formatting dates with ordinal suffixes