Yesterday I have setup a new mapping to a Webdav resource from some of my Windows 7 clients and discovered that I couldn't copy files larger than 50 MB from the IIS Webdav server. The error that was shown when trying to copy was this one: 'Error 0x800700DF: The file size exceeds the limit allowed and cannot be saved '.
This is a due to a built-in parameter which is specified for the Webclient service on Windows 7. By default this service will refuse to copy a large file toward a Webdav destination (such as a IIS/SharePoint web folder) and need therefore to be explicitely configured for larger files upload.
This is done with the help of the FileSizeLimitInBytes registry key under HKLM\SYSTEM\CurrentControlSet\Services\WebClient\Parameters. This registry key specifies the maximum size that the WebClient service allows for file transfers. Its size is in bytes and its default value is 50,000,000 decimal.
For simplicity, my suggestion is to set it up to its maximum value by adding two zeros to the predefined value, then click ok and let the system bring it back to the maximum allowed value for a 32-bit key, which is 4294967295 in decimal or ffffffff in hexadecimal. Faster than typing isn'it?
Unfortunately closing the registry won't solve immediately this problem. So restart the Web Client service using Services.msc or reboot and the problem is forever solved.