This website contains links to software which is either no longer maintained or will be supported only until the end of 2019 (CKFinder 2). For the latest documentation about current CKSource projects, including software like CKEditor 4/CKEditor 5, CKFinder 3, Cloud Services, Letters, Accessibility Checker, please visit the new documentation website.

If you look for an information about very old versions of CKEditor, FCKeditor and CKFinder check also the CKEditor forum, which was closed in 2015. If not, please head to StackOverflow for support.


When installing and configuring CKFinder, sometimes it may happen that for unknown reason CKFinder doesn't work as expected, for example it returns an error about insufficient permissions ("It was not possible to complete the request due to file system permission restrictions."). In such case it might be more usable to run the debug version of server connector to find out what's the problem.


To use CKFinder for ASP.NET in debug mode, add <compilation debug="false"/> to the web.config.

<compilation debug="true" />


Apart from setting compilation element, the debug version of CKFinder binaries: CKFinder.dll and CKFinder.pdb should be copied to the "bin" directory of ASP.NET application. Both files are available in the ckfinder/bin/Debug directory.

When debugging problems with file uploads, using a tool to trace HTTP connections, like Fiddler, might be helpful.

Warning: it is not recommended to run production ASP.NET applications with debug mode enabled.

Disabling FCN

When File Change Notifications (FCN) are turned on, session state may be lost after deleting a subfolder. See this blog post on msdn to find out more about this issue. This might be a problem when using CKFinder, i.e. user might be automatically logged out after deleting a folder.

A resolution for this problem (apart from suggestions in the blog post mentioned above) is using a special HTTP module that disables FCN provided with CKFinder, named StopAppDomainRestartModule. To enable this module, add the following to web.config inside the <system.web> element:

<add name="StopAppRestartOnFolderDelete" type="CKFinder.Utils.StopAppDomainRestartModule" />

Note: this solution will not work in medium trust environment.

This page was last edited on 28 May 2010, at 08:46.