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Faculty of Mathematics

WinSynCMS problem when running on Windows 8

Some users have experienced problems when running WinSynCMS under Windows 8, backups never finish. The fix for this involves using a few command line instructions and a very small install of Cygwin. Note, this needs to be done every time you make a public/private SSH key pair!

The problem

The cause of the 'hanging' is because the Cygwin command WinSynCMS uses, under windows 8, will error with:

Permissions 0660 for 'C:\\Users\\{username]\\Appdata\\Local\\Temp\\WinSynCMS\\WinSynCMS' are too open.
It is required that your private key files are NOT accessible by others.
This private key will be ignored.

The file C:\\Users\\{username]\\Appdata\\Local\\Temp\\WinSynCMS\\WinSynCMS is your private SSH key, if this is ignored nothing will work. WinSynCMS has been updated to now look for this error and do something sensible - like point you to this page.

If you want to prove this, open a normal Windows command window (Windows KEY + R. Type 'cmd' (no quotes). Press OK). Type the following substituting 'WIBBLE' with your local account name on your PC and substituting 'CRSid' for your Maths CRSid e.g. cm214. The command below is for a 64bit install of Windows 8, if you've got a 32bit install, change c:\Program Files (x86)\ to c:\Program Files\

"c:\Program Files (x86)\WinSynCMS\Rsync\bin\ssh.exe" -2 -x -o 'userknownhostsfile "c:\Program Files (x86)\WinSynCMS\etc\known_hosts"' -o preferredauthentications=publickey -i C:\Users\WIBBLE\AppData\Local\Temp\WinSynCMS-ssh_keys\WinSynCMS

You'll probably see an error message like that at the top of this page, 'WARNING: UNPROTECTED PRIVATE KEY FILE!'. Once the fix has been done, running the command above, this time you should see:

PRI(4):Thu Nov 20 16:54:54 2014: Tardis user: cm214 backupsdir: /local/tardis/la
ptops/cm214 tag:  cmd:
PRI(0):Thu Nov 20 16:54:54 2014: No command found!  Not a valid way to connect!
Connection to closed.

The 'No command found!' is what you should get, don't worry about the fact you weren't able to SSH in, terminal SSH'ing into tardis has been disabled.

So what do I need to do?

The permission of your private key has to be changed and to do this, an install of Cygwin needs to be on your PC. You can either download Cygwin for yourself from or download the files from HERE are the files needed for a basic install of Cygwin, download and unzip the zip file. Then download and run the x86 setup program from Cygwin - and do an 'Install from Local Directory' and point to the unzip'ed files. Once installed, open a Cygwin command window - usual place will be C:\Cygwin\Cygwin.bat. Then type in the following commands:

cd /cygdrive/c/Users/$USER/AppData/Local/Temp/
chgrp -R Users WinSynCMS-ssh_keys/
chmod 600 WinSynCMS-ssh_keys/WinSynCMS

You can then remove Cygwin. There is no uninstaller, it's best to see for detailed instructions (basically delete the directory you install Cygwin into and delete any Desktop and/or Start Menu shortcuts if you chose to add them as part of the Cygwin install.).

That's is, UNLESS................. you create a new SSH key pair in which case you'll need to do the chmod'ing etc again!