Hi, in I documented beginners errors (unquoted pathnames containing spaces) not only in Microsoft products. Microsofts developer documentation but shows these beginners errors too (and is inconsistent, even in single topics). Examples: | HKEY_CLASSES_ROOT | txtile ... | Shell ... | cmd2 ... | command | (Default) = C:\Program Files\Windows NT\Accessories\wordpad.exe %1 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~ | [HKEY_CLASSES_ROOT\Applications\VSLauncher.exe\Shell\Open\Command] | @="C:\\Program Files\\Common Files\\Microsoft Shared\\MSEnv\\VSLauncher.exe \"%1\"" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | [HKEY_CLASSES_ROOT\VisualStudio.csproj.8.0\shell\Open\Command] | @="\"C:\\Program Files\\Common Files\\Microsoft Shared\\MSEnv\\VSLauncher.exe\" \"%1\"" | HKEY_LOCAL_MACHINE | SOFTWARE | Classes | contoso-search | shell | open | command | (Default) = "%ProgramFiles%\Contoso\Search\contososearch.exe %1" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~ | HKEY_LOCAL_MACHINE | SOFTWARE | Classes | LitwarePlayer11.AssocFile.... ... | shell | open | command | (Default) = %ProgramFiles%\Litware\litware.exe ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | HKEY_CLASSES_ROOT | CLSID | {0052D9FC-6764-4D29-A66F-2F3BD9E2BB40} | Shell | Open | Command | (Default) = [REG_EXPAND_SZ] %ProgramFiles%\MyCorp\MyApp.exe /Settings ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | | | @myTextResources.dll,-100 | @myTextResources.dll,-101 | %ProgramFiles%\Microsoft Games\Solitaire\solitaire.exe ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | Example with ambiguous/inconsistent use of quotes: | HKEY_CLASSES_ROOT | alert | (Default) = "URL:Alert Protocol" ^ ^ | URL Protocol = "" ^^ | DefaultIcon | (Default) = "alert.exe,1" ^ ^ | shell | open | command | (Default) = "C:\Program Files\Alert\alert.exe" "%1" Counterexamples: | Note: If any element of the command string contains or might contain | spaces, it must be enclosed in quotation marks. Otherwise, if the | element contains a space, it will not parse correctly. For instance, | "My Program.exe" starts the application properly. If you use | My Program.exe without quotation marks, then the system attempts to | launch My with Program.exe as its first command line argument. You | should always use quotation marks with arguments such as "%1" that are | expanded to strings by the Shell, because you cannot be certain that | the string will not contain a space. regards Stefan Kanthak