
Hello @Yana Chen ,
Welcome to Q&A Forum!
In my test, I cannot reproduce your problem.
SharePoint Designer >> All Files >> Lists >> select list that you wanted and upload form files
I suggest you perform the following troubleshootings:
1.Click the Refresh button in the list properties view
2.Clear SharePoint Designer cache follow the below steps:
- Close SharePoint Desginer
- Delete everything from %APPDATA%\Microsoft\Web Server Extensions\Cache
- Delete everything from %APPDATA%\Microsoft\SharePoint Designer\ProxyAssemblyCache
- Delete everything from %USERPROFILE%\AppData\Local\Microsoft\WebsiteCache
- Delete everything from %APPDATA%\Microsoft\SharePoint Designer
- Now open SharePoint Designer and try to reconnect your site.
Thanks,
Echo Du
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