ASP.NET HTTP error 500.19 "cannot read config file" - asp.net

Question

I have a really frustrating problem. I have a website in ASP.NET. I use IIS Express for development. I recently moved my project files and folders from a usb drive to my dropbox folder to avoid carrying the drive around.
After moving my project to the dropbox folder, I got this error that IIS cannot read my config file. I noticed the path was pointing to my usb drive. So I copied my web.config to the path displayed in the error message and it worked again, if I delete it again, the error comes again.
So I think that somewhere in my project there is a config setting that points to my usb drive, although it should point to my local dropbox folder.
I have attached a screenshot of the error:
Translation:
Module IIS Web Core
Message Unknown
Handler still undetermined
Error code 0x80070003
Config error The config file cannot be read
Config file .........
Requested URL ...........
Physical path
Authentication method still unknown
Authenticated user still unknown
Debug path ..................

Answer 1

I had this problem when trying to launch a service from a project created on another machine that was saved in DropBox.
In the project folder there is a file in PROJECTFOLDERNAME/.vs/config/applicationhost.config
In that file is a list of sites in XML like so:
<sites>
<site name="WebSite2" id="2">
<application path="/" applicationPool="Clr4IntegratedAppPool">
<virtualDirectory path="/" physicalPath="C:\Users\WRONGPATH\Dropbox\Website2\src\Website2" />
</application>
<bindings>
<binding protocol="http" bindingInformation="*:64655:localhost" />
</bindings>
</site>
<site name="WebSite4" id="3">
<application path="/" applicationPool="Clr4IntegratedAppPool">
<virtualDirectory path="/" physicalPath="C:\Users\Nick\Dropbox\Website3\src\Website3" />
</application>
<bindings>
<binding protocol="http" bindingInformation="*:64655:localhost" />
</bindings>
</site>
<siteDefaults>
<logFile logFormat="W3C" directory="%IIS_USER_HOME%\Logs" />
<traceFailedRequestsLogging directory="%IIS_USER_HOME%\TraceLogFiles" enabled="true" maxLogFileSizeKB="1024" />
</siteDefaults>
<applicationDefaults applicationPool="Clr4IntegratedAppPool" />
<virtualDirectoryDefaults allowSubDirConfig="true" />
</sites>
Change the virtualDirectory physicalPath to the correct path. The problem I still face is I work on this project from two different locations, I don't really want to change this back and forth all the time.

Answer 2

Uhh, I have looked for the answer for more than 2 hours. I tried cleaning up every bin, .vs folders. But those did not help me.
Eventually, I fixed the issue by re-showing (re-binding) the path to the project in IIS Manager

Answer 3

I had this issue when I moved my "My Documents" folder to another location. IIS Express was still pointing to old path. The only way I could fix this is by doing clean installation of IIS Express.
Uninstall IIS Express
Remove the 'IIS Express' folder that contains configuration file.
Install IIS Express