--- title: "Windows file name length limits" canonical_url: "https://www.nutrient.io/guides/document-automation-server/document-conversion/file-name-length/" md_url: "https://www.nutrient.io/guides/document-automation-server/document-conversion/file-name-length.md" last_updated: "2026-06-09T10:25:14.364Z" description: "Learn how to avoid issues with file name lengths in Windows, ensuring smooth operations in Document Automation Server by adjusting UNC paths and settings." --- # Managing Windows file name length in DAS Windows has a file name length limit of 260 characters and a folder name length limit of 248 characters. There are two areas where this could potentially impact Nutrient Document Automation Server (DAS) — previously known as Document Automation Server (DAS) — processing. ## File name length — UNC paths If a local file path is at or close to one of the Windows limits, it can potentially cause issues — for example, if the file path is equal to or more than 260 characters: `C:\documents\major accounts payable 2010\\......with 260 characters.pdf` When the file above is accessed remotely via a universal naming convention (UNC), as shown below, it’ll exceed the 260 character Windows file name limit during Nutrient DAS processing. This can even affect files that are to be filtered out — for example, `.msg` files in the case where `.pdf` has been specified as a filter. `\servername\c$:\documents\major accounts payable 2010\.......with 260 characters.pdf` The best solution for this problem is to create a share so that the UNC path won’t exceed the limit. For example, create a share to `C:\documents\major` accounts payable 2010 with a short name such as `dp2`. This will allow access via a UNC such as `\\servername\dp2\.......with 260 characters.pdf`. In other words, in Designer, the source folder is `\\servername\dp2` rather than `\\servername\c$:\documents\major accounts payable 2010`. ## File name length — Nutrient DAS working folder paths For integrity reasons, Nutrient DAS will, by default, copy source files and write processed files to work folders before copying to the target output folders. The location of work folders is defined in the job manager — for example, `C:\Aquaforest\Autobahn DX\work\1008`. As an example, given a file named `C:\Accounts\Business Documents 2010\Invoices\......with 260 characters.pdf` and the source folder defined as `C:\Accounts\Business Documents 2010\Invoices`, the work folder will be `C:\Aquaforest\Autobahn DX\work\1008\ Invoices\....with 260 characters.pdf,` which will exceed the limit. The best solution is to shorten the work folder path via the Designer screen — for example, to `C:\dw\1008` instead of `C:\Aquaforest\Autobahn DX\work\1008`. ## Long file name support Starting in Windows 10 and Windows Server 2016, version 1607, `MAX_PATH` limitations have been removed from common Win32 file and directory functions. However, you must opt in to the new behavior. This section will show you how to configure your computer and Nutrient DAS to use long file names. ### Nutrient DAS configuration - Open the Nutrient DAS configuration file found in the location below: - `“Autobahn Install Folder\ config\Autobahn.config”` - Set the `“allowlongfilename”` value to `“True”`, as shown below: - `` ### Windows configuration - Start the registry editor (`regedit.exe`). - Navigate to `HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem`. - Double-click `LongPathsEnabled`. - Set its **Value data** to `1` and click **OK**. - Reboot. --- ## Related pages - [Comprehensive guide to document automation servers](/guides/document-automation-server/document-conversion/acknowledgments.md) - [Essential configuration files for Document Automation Server](/guides/document-automation-server/document-conversion/autobahn-dx-configuration-files.md) - [Explore document automation server directories](/guides/document-automation-server/document-conversion/autobahn-dx-directories.md) - [Efficiently execute jobs with the DAS .NET API](/guides/document-automation-server/document-conversion/autobahn-dx-net-api.md) - [Split and rename PDF files using barcode detection](/guides/document-automation-server/document-conversion/barcode-support.md) - [Streamline your document processing jobs](/guides/document-automation-server/document-conversion/autobahn-dx-quick-start.md) - [Optimizing load balancing with distributed polling](/guides/document-automation-server/document-conversion/distributed-polling.md) - [Streamline PDF management with advanced automation](/guides/document-automation-server/document-conversion/dascontentextraction-kingfisher-job-step.md) - [Enhance document processing with the .NET SDK](/guides/document-automation-server/document-conversion/gdpicture-additional-steps.md) - [Enhanced cloud OCR capabilities for text recognition](/guides/document-automation-server/document-conversion/cloud-ocr.md) - [Streamline your document conversion processes](/guides/document-automation-server/document-conversion.md) - [Essential document automation server installation guide](/guides/document-automation-server/document-conversion/installation-and-licensing.md) - [Optimize OCR with advanced preprocessing options](/guides/document-automation-server/document-conversion/ocr-properties-file-and-the-advanced-pre-processing-option.md) - [Extract key-value pairs from PDFs to JSON](/guides/document-automation-server/document-conversion/pdf-recognition-to-json-job-step.md) - [Automate document processing with custom scripts](/guides/document-automation-server/document-conversion/scripting-custom-steps.md) - [Streamline document automation with XML job definitions](/guides/document-automation-server/document-conversion/job-definition-xml-files.md) - [Enhance document processing with multicore support](/guides/document-automation-server/document-conversion/multicore-support.md) - [Effortlessly convert files to PDF with ToPDF](/guides/document-automation-server/document-conversion/topdf-bcl-easypdf.md) - [Upgrade Document Automation Server](/guides/document-automation-server/document-conversion/release-notes.md) - [Streamline document processing with automation](/guides/document-automation-server/document-conversion/product-overview-and-concepts.md)