On 1/13/20, Mike Weaver <miwea...@gmail.com> wrote: > > I've tried downloading from https://www.python.org/downloads/windows/ > (the Windows x86-64 executable installer > <https://www.python.org/ftp/python/3.8.1/python-3.8.1-amd64.exe>) > and running that. Again says it is installed - but it clearly isn't.
Maybe you didn't enable the option to add the installation directory to PATH. Modifying the system and per-user PATH value is easy enough -- especially in Windows 10, which provides an exploded view of the semicolon-delimited list of directories, with individual entries that you can edit or move up and down in the list. > If I open a command prompt and type 'python', I get > > TCC: (Sys) The file cannot be accessed by the system > "C:\Users\Mike\AppData\Local\Microsoft\WindowsApps\python.exe" > > If I search in that directory, I find a <SYMLINK> to python.exe. I have That's the app-exec link for the store version of Python, which, if it's not installed, actually targets a stub app that opens the Microsoft Store to install Python. The directory of the standard installation needs to precede "%LocalAppData%\Microsoft\WindowsApps" in PATH in order to avoid this app-exec link. The default installation directory for x64 3.8 would be "%ProgramFiles%\Python38" for a system install and "%LocalAppData%\Programs\Python\Python38" for a per-user install. Note that an app-exec link is a type of filesystem reparse point, like a symlink or mount point in that narrow aspect, but it is most definitely not a symlink. Your shell is wrong to report that it's a "<SYMLINK>". There's no kernel handler for this type of reparse point, so any attempt to open it normally, with reparsing enabled, will fail as an unhandled reparse point. As far as I know, no Cygwin-derived environment (e.g. MSYS2) has been updated to support app-exec links. The onus is on these frameworks to stay up to date with significant changes in Windows. CreateProcess handles app-exec links in user mode. It directly opens the reparse point to read the target executable path. It also reads a set of security attributes, which it adds to a custom access token for the child process (i.e it's like a CreateProcessAsUser call). The security attributes in the access token allow the child process to access the app's files in "%ProgramFiles%WindowsApps\<app directory>", which are protected by a conditional access-control entry. -- https://mail.python.org/mailman/listinfo/python-list
