Creating Shell Extension Servers can be extremely difficult, as diagnosing issues is very hard. The most common problem encountered is that a server seems to work with the ServerManager tool, but simply doesn't show up at all in Windows Explorer. This page pulls together a detailed guide of how to troubleshoot servers.
- Server not showing in Windows Explorer
- Shell Thumbnail Handlers
- Shell Icon Overlay Handlers
- Shell Property Sheet Extensions
- Context Menu Extensions
- The DirectoryBackground ComServerAssociation
- Preview Handlers
- The File Type Verifier
First, check the troubleshooting guide in the Installing documentation.
Important: For most SharpShell servers to work on anything other than a development machine, they MUST be built in Release Mode against the Release Mode SharpShell binary. This binary uses an unmanaged C++ component that has a dependency to MSVCRTD100.dll in debug mode - this will NOT be present on none-development machines.
Shell thumbnail handlers have some specific things to be aware of:
- Do NOT use 'ClassOfExtension' COM server associations - you must register to a file extension.
- The Server Manager tool doesn't seem to respect alpha channels, but the system does.
You cannot create a Shell Thumbnail Handler which is based in IInitializeWithItem, this exposed security issues and was disabled in Windows 10, see the thread here:
See also the Stack Overflow question here:
If you are not seeing your Shell Icon Overlay handlers after registering, double check which other icon handlers are registered, if you have more than a few then yours may not show up - the shell only supports about ten or so.
Overlays are registered at:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\ShellIconOverlayIdentifiersHKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\explorer\ShellIconOverlayIdentifiers
Check these nodes to make sure you do not have too many overlays already registered.
You can also use the RegistrationName attribute on a server to force a name to be used for the registration which will move the server to a high position in the list. For example:
[RegistrationName(" ReadOnlyFileIconOverlayHandler")] // push our way up the list by putting spaces in the name...
public class ReadOnlyFileIconOverlayHandler : SharpIconOverlayHandlerOn 32 bit systems, it normally takes a restart if explorer.exe for the icon to be loaded. Apparently, this can actually be done programatically via SHChangeNotify.
If you see a cross icon instead of your icon, make sure the build action for the icon is set to "Resource". If this doesn't work, try copying it to the resource folder manually. (See http://www.codeproject.com/Articles/545781/NET-Shell-Extensions-Shell-Icon-Overlay-Handlers?msg=4972010#xx4972010xx).
Multiple Icon Handlers showing the same icon
If all of your icon overlay handlers use classes with the same name, then only one class's icons will be shown. Explorer caches Handlers and their icons in the %temp% folder. The name of the icon takes from the name of class and all of handlers used one icon. This means if you have duplicate class names then the correct icons will not be used. See Issue #373 for more details on this.
For property sheet extensions to work, make sure that the destination machine has the Visual C++ 2012 Redistributables installed (vcredist_x86 or vcredist_x64).
It seems that under some circumstances, Tab Controls in property sheet extensions can lead to unpredictable behaviour and crashes - currently I recommend against using them until the route cause of this issue is identified. More detail on this issue and the one above can be found here: https://sharpshell.codeplex.com/discussions/470807
...2) The second issue I found with the PropertyPageHandler is in combination with a TabControl. It doesn't matter if the TabPages are created dynamically or in static way. When I switched (on my developer machine) between the PropertyPage and any other application (sometimes 2 times focus switch, sometimes after 10 times focus switches between the applications) the PropertyPage freezes and then the Windows Explorer crashes with an AppHangB1. Fast workaround is of course the usage of any other controls. I have this tested this only on one machine (my developer machine), so maybe this is only a very specific issue. Thread #470807 | Message #1127814 | 2013-11-22
It seems that sometimes creating the [ComServerAssociation] is not enough. When you add the registry key for the given extension, the context menu may be got from a different part of the registry for the users preference. For example, for 'png', uou can determine this by checking the user choice:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts.png\UserChoice
This will give you the progid gives you the keyname to associate with the server. In this case, it might be WindowsLive.PhotoGallery.png.16.4.
I did this manually and hey presto it works.
Note that if you have a DirectoryBackground COM Server Association, then the directory you are in will not be in the SelectedItemPaths (as it is not actually selected). To get this directory, simply use the FolderPath property. (See #68 for more details).
If you find your preview handler for Directories is not working on a client machine, trying installing and registering it both **both **x86 and x64. Thanks Umut Ozel!
The File Type Verifier tool from Microsoft can also be used to get some diagnostic reports on Shell Extensions associated with file types. Details are here: http://msdn.microsoft.com/en-us/library/windows/desktop/hh127466