Why are web config files not identical on all machines in the farm?
Rule Name: Web.config files are not identical on all machines in the farm. Summary: If you have multiple front-end Web servers in the farm and have made manual changes to the Web.config files, you will experience a problem where a front-end Web server cannot read session state that was saved by another server in the farm.
Where do I find applywebconfigmodifications in web.config?
When troubleshooting web.config modifications, examine the SPWebApplication.WebConfigModifications and SPWebService.WebConfigModifications properties as well as the physical file. Code that calls ApplyWebConfigModifications works only if it runs in the user context of an administrator on the front-end web server.
Where is the web.config file stored on the server?
Log on to the server on which this event occurs. Typically the Web.config file is stored at C:\\inetpub\\wwwroot\\wss\\VirtualDirectories\\Port_Number. Note the modified date of the Web.config file. Repeat the previous steps on other failing servers. Compare these Web.config files and decide which one is correct.
How to extend web.config file programmatically?
Code that calls ApplyWebConfigModifications works only if it runs in the user context of an administrator on the front-end web server. For information about a second way of extending web.config files, see How to: Create a Supplemental .config File.
How to view web.config file in Server Manager?
To view the content of the Web.config file, do the following: In Server Manager, click Tools, and then click Internet Information Services (IIS) Manager.
What to do if your server farm is failing?
If there are multiple failing servers in a server farm, you must repeat the following steps on each failing server. Verify that the user account that is performing the following steps is a member of the Administrators group on the local computer that you identified in the previous step.
How to delete the wrong web config file?
On the site Home page, switch to the Features View, and then in the Management section, double-click Configuration Editor. In the Section list, select a section to view the settings of the Web.config file. Delete the incorrect Web.config file on each failing server, and then copy and paste the correct Web.config file.