What causes FileNotFoundException?

A required .NET assembly (e.g., System.ValueTuple.dll) is absent from both the IR install directory and the Windows Global Assembly Cache. Incomplete or corrupted Self-Hosted IR installation where dependency files were not fully deployed. Manual deletion or antivirus quarantine of a file in the IR Gateway folder. Version mismatch: the assembly exists but the wrong version is present and the required version cannot be found via GAC binding redirects

How do I fix FileNotFoundException?

Step 1: Read the full exception message to identify the exact assembly name and version that cannot be found (e.g., 'System.ValueTuple, Version=4.0.2.0, PublicKeyToken=XXXXXXXXX').. Step 2: Search for the DLL on the IR host machine in C:\Program Files\Microsoft Integration Runtime\4.0\Gateway\ and in %windir%\Microsoft.NET\assembly; note whether the file is absent entirely or present in the wrong version.. Step 3: Obtain the correct version of the assembly — either by installing the relevant NuGet package offline, copying it from another healthy IR node, or installing the required .NET Framework update — and place it in the IR Gateway folder.. Step 4: Check that antivirus or endpoint protection software has not quarantined IR files; add the IR installation directory to the antivirus exclusion list if necessary.. Step 5: Restart the Self-Hosted IR service and re-run the pipeline to confirm the file is now resolved correctly.

High severityconfigurationAzure Data Factory →

Power BI Refresh Error:
FileNotFoundException

What does this error mean?

The Self-Hosted IR could not locate a required DLL or assembly file at runtime, preventing the activity from executing. This commonly appears as an inner exception beneath TypeInitializationException when a connector driver dependency is missing.

Common causes

1A required .NET assembly (e.g., System.ValueTuple.dll) is absent from both the IR install directory and the Windows Global Assembly Cache
2Incomplete or corrupted Self-Hosted IR installation where dependency files were not fully deployed
3Manual deletion or antivirus quarantine of a file in the IR Gateway folder
4Version mismatch: the assembly exists but the wrong version is present and the required version cannot be found via GAC binding redirects

How to fix it

1Step 1: Read the full exception message to identify the exact assembly name and version that cannot be found (e.g., 'System.ValueTuple, Version=4.0.2.0, PublicKeyToken=XXXXXXXXX').
2Step 2: Search for the DLL on the IR host machine in C:\Program Files\Microsoft Integration Runtime\4.0\Gateway\ and in %windir%\Microsoft.NET\assembly; note whether the file is absent entirely or present in the wrong version.
3Step 3: Obtain the correct version of the assembly — either by installing the relevant NuGet package offline, copying it from another healthy IR node, or installing the required .NET Framework update — and place it in the IR Gateway folder.
4Step 4: Check that antivirus or endpoint protection software has not quarantined IR files; add the IR installation directory to the antivirus exclusion list if necessary.
5Step 5: Restart the Self-Hosted IR service and re-run the pipeline to confirm the file is now resolved correctly.

Frequently asked questions

Can I resolve this without restarting the Integration Runtime service?

No — .NET assembly loading happens at process startup or on first use. After placing the missing DLL in the correct location, a service restart is required for the IR process to pick up the new file.

How do I find the correct version of the missing assembly to download?

The full assembly identity (name, version, culture, PublicKeyToken) is listed in the exception message. Use NuGet.org to find the package containing that assembly, download the package offline, and extract the DLL matching the required version.