Path character limit (gotcha)
We've been really excited for FileMaker 12 Server and its external container storage feature. It's been an extremely popular feature with our clients, but with new technology, brings new potential issues.
One issue we've recently run into is, OS path length restrictions with Windows Server 2008 R2. The documented maximum length seems to be around 260 characters on Windows OS (and 1024 characters on Mac OS).
The error we see is (we generalized the path names, file names and field names): 2013-02-26 17:01:34.216 -0800 Error 852 [Record ID 15666, field FileMaker Table Name::Container Field Name] Saving container data resulted in error (852): Can not write file to the external storage.
When we took a look at the path being used by external containers, we see something like this:
C:\Program Files\FileMaker\FileMaker Server\Databases\User Folder Name\RC_Data_FMS\FileMaker Database File Name\Files\FileMaker Database File Name\FileMaker Table Name Here\FileMaker Field Name Here\Record Info\Image or document name here.ext
(again, we generalized the path names)
As you can see, it can be very easy to approach the Windows path length limit. The above is around 242 characters. Database users and administrators should be conscience of all aspects of naming, most importantly the calculated path for for the externally stored path and the file name of the object being placed into the container field.
We hope this helps someone who is troubleshooting this type of issue on Windows OS.