Failed to start monitoring changes to 'path' because access is denied.

Problem:

Brought up a web page and was presented with this error:

Server Error in '/' Application.

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Failed to start monitoring changes to 'C:\Users\xxxx\AppData\Local\Temp\Temporary ASP.NET Files\root\b6230deb\7677a327\hash\hash.web' because access is denied.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.Web.HttpException: Failed to start monitoring changes to 'C:\Users\xxxx\AppData\Local\Temp\Temporary ASP.NET Files\root\b6230deb\7677a327\hash\hash.web' because access is denied.

Source Error: 

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace: 

[HttpException (0x80070005): Failed to start monitoring changes to 'C:\Users\xxxx\AppData\Local\Temp\Temporary ASP.NET Files\root\b6230deb\7677a327\hash\hash.web' because access is denied.]    System.Web.DirectoryMonitor.AddFileMonitor(String file) +8805891    System.Web.DirectoryMonitor.StartMonitoringFileWithAssert(String file, FileChangeEventHandler callback, String alias) +94    System.Web.FileChangesMonitor.StartMonitoringFile(String alias, FileChangeEventHandler callback) +340    System.Web.Compilation.BuildManager.CheckTopLevelFilesUpToDate2(StandardDiskBuildResultCache diskCache) +790    System.Web.Compilation.BuildManager.CheckTopLevelFilesUpToDate(StandardDiskBuildResultCache diskCache) +55    System.Web.Compilation.BuildManager.RegularAppRuntimeModeInitialize() +174    System.Web.Compilation.BuildManager.Initialize() +261    System.Web.Compilation.BuildManager.InitializeBuildManager() +246    System.Web.HttpRuntime.HostingInit(HostingEnvironmentFlags hostingFlags, PolicyLevel policyLevel, Exception appDomainCreationException) +350   [HttpException (0x80004005): Failed to start monitoring changes to 'C:\Users\xxxx\AppData\Local\Temp\Temporary ASP.NET Files\root\b6230deb\7677a327\hash\hash.web' because access is denied.]    System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +8950644    System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +97    System.Web.HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr) +258

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Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.1

Solution:

First, I had to close Visual Studio 2010, then I deleted c:\Users\xxxx\AppData\ocal\Temp\Temporary ASP.NET Files.

Reopened Visual Studio and ran it again in debug mode, worked fine.