How to fix: Custom List Forms will not insert or show up on the Design surface of SharePoint Designer

When attempting to insert a custom list form in SharePoint Designer the form never displays in design view. There is no error message, and the form never gets inserted into the page.

Fixes

You’ll need to reinstall SP1 using our recommendations:

• http://technet.microsoft.com/en-us/library/cc288269.aspx
• http://support.microsoft.com/kb/945013/

Method 2 – Clean up the user profile.

You’ll need to clean up the user profile using these steps:

1. Close SharePoint Designer 2007.
2. Clear your Internet Explorer’s temporary Internet cache.
3. Open My Computer and go to %System Drive%\Documents and Settings\%user%\Local Settings\Application Data\Microsoft\WebSiteCache (If you are running Vista, that path is different – look for %System Drive%\Users\%user%\AppData\Local\Microsoft\WebSiteCache).
4. Go to a directory that looks similar to the name of the website you were connecting to.
5. Delete the assembly with the name of your SharePoint Site.
6. Type %temp% at a run prompt and delete all the temp files in there.
7. Delete the contents of: C:\Documents and Settings\username\Application Data\Microsoft\Web Server Extensions\Cache.