Considerations
When running a workspace in FME Flow that reads data directly from a ZIP file, the translation may fail with generic “file could not be opened” errors. These errors can vary by format and may not clearly indicate the root cause. Examples include:
Geodatabase Error (-2147024893): The system cannot find the path specified. Could not open File Geodatabase dataset `<filepath>' for readingMITAB Reader: Failed to open and parse file '<filepath>'. Make sure that the file exists and is valid
This behavior is most commonly encountered on Windows systems when working with deeply nested ZIP contents or long file names.
Why This Happens
Windows enforces a default maximum path length of 260 characters. This limitation can affect how FME Flow Engines access data extracted from ZIP files. When a workspace references a dataset inside a ZIP file, FME Flow automatically extracts the contents to a temporary directory. The full extraction path includes:
- Engine name
- Temporary folder structure
- ZIP file name
- Internal folder structure
- Target file name
This can quickly result in very long file paths. Temporary extraction locations depend on how the FME Flow Engine service is run. Below are examples of the default file paths for engines running on service accounts and on the local system
- Service account:
C:\Users<username>\AppData\Local\Temp\fmeengines<EngineName> - Local System account:
C:\Windows\TEMP\fmeengines<EngineName>
If the fully expanded path exceeds 260 characters, Windows cannot access the file, and the translation fails. Because of this, FME Flow may return a generic “unable to open file” error instead of identifying the path length limitation.
How to Resolve It
There are two approaches to preventing this issue:
Option 1: Enable Long Path Support (Recommended)
Enable long path support in Windows to allow longer file paths.
1. Open the Windows search bar and type Group Policy. Select Edit group policy.
2. Navigate to: Computer Configuration > Administrative Templates > System > Filesystem and double click on Enable Win32 long paths
3. Set the option to Enabled. Click Apply and then OK.
4. Restart the FME Flow Engine service
This allows Windows to support significantly longer file paths and prevents failures during ZIP extraction.
Option 2: Shorten File Paths
If enabling long paths is not possible, reduce the total path length by:
- Shortening the ZIP file name
- Reducing folder depth inside the ZIP
- Renaming long subfolders or file names
These changes reduce the likelihood of exceeding the path length limit during extraction.