Can't open .c4 files

[johnsmith88]

Hi folks,

I can't open .c4 (JEDMICS) files by double clicking on them. XnView just opens to the blank screen (or the Browser if you have that set to open on program start). The file opens if I go to File > Open, or by dragging the file icon onto XnView. It just doesn't open by double click. Likewise doesn't open by clicking links to .c4 files from a webpage. "Display all image file types" is enabled.

However, XnView MP works by double clicking the file. At least on this computer. But if I try it on another computer, neither Classic or MP can open on double click. So the problem is not really consistent. All other compatible filetypes open just fine.

Is this an XnView setting somewhere, or a Windows setting?

Thanks.

[xnview]

do you have Settings>Display all file formats?

[johnsmith88]

Yes sir. I can open the file by dragging it onto XnView, or by using File > Open. But if I double click on the file, it just opens XnView to a blank screen.

[xnview]

you need check the registry entry for .C4

[johnsmith88]

I thought it might have something to do with the registry. Any particular registry entry I should look at?

[johnsmith88]

Any idea what values I should change or delete in the registry? Thanks.

[xnview]

Any idea what values I should change or delete in the registry? Thanks.

please check .c4 entry in HKCR

[johnsmith88]

Here is the entry for HKEY_CLASSES_ROOT\.C4
(Default) string with data C4_auto_file

Is this correct?

[xnview]

and what do you have in C4_auto_file?

[johnsmith88]

I've been doing a little digging. Sorry for my ignorance. C4_auto_file appears several times in the registry. But I'm not really sure what to do with it. Attached is a screenshot of all the locations it appears. I'm not sure if you can gain any information from it. We might be at a dead end here. Thanks.

Code: Select all

Windows Registry Editor Version 5.00


[HKEY_USERS\S-1-5-21-4276474514-3336788208-196049622-361428_Classes\C4_auto_file\shell\open\command]
""="\"C:\\Soft\\XnViewMP\\xnviewmp.exe\" \"%1\""

[HKEY_USERS\S-1-5-21-4276474514-3336788208-196049622-361428_Classes\.C4]
""="C4_auto_file"

[HKEY_USERS\S-1-5-21-4276474514-3336788208-196049622-361428_Classes\]
""="C4_auto_file"

[HKEY_USERS\S-1-5-21-4276474514-3336788208-196049622-361428\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.C4\OpenWithProgids]
"C4_auto_file"=hex(0):

[HKEY_USERS\S-1-5-21-4276474514-3336788208-196049622-361428\SOFTWARE\Microsoft\Windows\CurrentVersion\ApplicationAssociationToasts]
"C4_auto_file_.C4"=dword:00000000

[HKEY_USERS\S-1-5-21-4276474514-3336788208-196049622-361428\SOFTWARE\Classes\C4_auto_file\shell\open\command]
""="\"C:\\Soft\\XnViewMP\\xnviewmp.exe\" \"%1\""

[HKEY_USERS\S-1-5-21-4276474514-3336788208-196049622-361428\SOFTWARE\Classes\.C4]
""="C4_auto_file"

[HKEY_USERS\S-1-5-21-4276474514-3336788208-196049622-361428\SOFTWARE\Classes\]
""="C4_auto_file"

[HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.C4\OpenWithProgids]
"C4_auto_file"=hex(0):

[HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\ApplicationAssociationToasts]
"C4_auto_file_.C4"=dword:00000000

[HKEY_CURRENT_USER\SOFTWARE\Classes\C4_auto_file\shell\open\command]
""="\"C:\\Soft\\XnViewMP\\xnviewmp.exe\" \"%1\""

[HKEY_CURRENT_USER\SOFTWARE\Classes\.C4]
""="C4_auto_file"

[HKEY_CURRENT_USER\SOFTWARE\Classes\]
""="C4_auto_file"

[HKEY_CLASSES_ROOT\C4_auto_file\shell\open\command]
""="\"C:\\Soft\\XnViewMP\\xnviewmp.exe\" \"%1\""

[HKEY_CLASSES_ROOT\.C4]
""="C4_auto_file"

[HKEY_CLASSES_ROOT\]
""="C4_auto_file"