Overwritting a file type association

[Nicolas Caron]

Hello,

I am trying to have my application overwrite a file type association
when it runs (to allow our users to associate our old file formats to
the newer version of our application).

I am going in HKEY_CLASSES_ROOT\MyFileType.Document\shell\Open\command

There just like I expected the default value points to the associated
application for this file type. That said there is also another value
named "command" of the REG_MULTI_SZ type that contains a bunch of
"random" characters. If I only overwrite the (Default), the file type
is still associated with the old application. If I delete the "command"
value, now the new value put in (Default) is taken into account.

So here's my question :
Is there any potential problems to deleting the "command" key? And if
so, how can I modify it to make sure the files now open with my new
application?

Thanks in advance

 

[Michael Bednarek]

I am trying to have my application overwrite a file type association
when it runs (to allow our users to associate our old file formats to
the newer version of our application).

I am going in HKEY_CLASSES_ROOT\MyFileType.Document\shell\Open\command

There just like I expected the default value points to the associated
application for this file type. That said there is also another value
named "command" of the REG_MULTI_SZ type that contains a bunch of
"random" characters. If I only overwrite the (Default), the file type
is still associated with the old application. If I delete the "command"
value, now the new value put in (Default) is taken into account.

So here's my question :
Is there any potential problems to deleting the "command" key? And if
so, how can I modify it to make sure the files now open with my new
application?

I've never seen a REG__MULTI_SZ (or any other type) value named
"command" below the key HKCR\MyFileType.Document\shell\Open\command - I
suspect it is, like so much in the Registry, the leftover of a some
malformed installation routine. Deleting it seems the right thing to do.

 

[Mark V]

I've never seen a REG__MULTI_SZ (or any other type) value named
"command" below the key
HKCR\MyFileType.Document\shell\Open\command - I suspect it is,
like so much in the Registry, the leftover of a some malformed
installation routine. Deleting it seems the right thing to do.

While I cannot answer the OP's questions in full, I believe he is
seeing MS Installer (MSI) strings. If an MSI installation was used
to install the application, these "command" valuenames could be the
result. Sorry to not have more details, but at least it's
something to research. Also try a registry search on one of those
strings (leave off any escaped chars at the end of string) and I
think you will find a multitude of entries.

 

[Nicolas Caron]

While I cannot answer the OP's questions in full, I believe he is
seeing MS Installer (MSI) strings. If an MSI installation was used
to install the application, these "command" valuenames could be the
result. Sorry to not have more details, but at least it's
something to research. Also try a registry search on one of those
strings (leave off any escaped chars at the end of string) and I
think you will find a multitude of entries.

After some digging we found out that this string seems related to DDE
in some way. I will therefore delete it without any second thoughts

Thanks

 

[Michael Bednarek]

While I cannot answer the OP's questions in full, I believe he is
seeing MS Installer (MSI) strings. If an MSI installation was used
to install the application, these "command" valuenames could be the
result. Sorry to not have more details, but at least it's
something to research. Also try a registry search on one of those
strings (leave off any escaped chars at the end of string) and I
think you will find a multitude of entries.

You are correct - I didn't look hard enough. Sure enough, all file types
associated with Microsoft Office show a registry value in my registry
(HKCR\...\shell\Open\command\command [REG_MULTI_SZ]) with some
unintelligible content.

I think I read something about these and how to decrypt them, but I
can't find those references now.

 

[Mark V]

[ ]
[ ]

You are correct - I didn't look hard enough. Sure enough, all
file types associated with Microsoft Office show a registry
value in my registry (HKCR\...\shell\Open\command\command
[REG_MULTI_SZ]) with some unintelligible content.

I think I read something about these and how to decrypt them,
but I can't find those references now.

If you find it, please post it!
There are a some microsoft.public.*.msi groups that may be a
resource.