I've switched on the full message output of the git console. (Tools > Options > General > Always display full console output)

I've noticed, when pulling changes into a branch, the console shows a syntax error:

git -c diff.mnemonicprefix=false -c core.quotepath=false fetch origin
\"C:/Program Files (x86)/GitExtensions/GitCredentialWinStore/git-credential-winstore.exe\" get: -c: line 0: syntax error near unexpected token `('

UPDATE:
This appears to be related to Git Extensions (also installed on my environment)
A resolution for this issue is posted at: https://lysandergg.wordpress.com/2014/06/21/git-extensions-syntax-error-near-unexpected-token/