(Perhaps this isn't a bug. I may be trying to do something the plugin is not designed to support.)

Git clone fails when using a CIFS network share as a repository. However, git clone command succeeds when run from the Windows command shell if double quotation marks are used to enclose each path. It seems that the command generated by the plugin is not syntactically correct.

Failure log output:

Started by user anonymous
Checkout:workspace / C:\Program Files (x86)\Jenkins\jobs\test 1\workspace - hudson.remoting.LocalChannel@1e9d0cc
Using strategy: Default
Checkout:workspace / C:\Program Files (x86)\Jenkins\jobs\test 1\workspace - hudson.remoting.LocalChannel@1e9d0cc
Cloning the remote Git repository
Cloning repository origin
ERROR: Error cloning remote repo 'origin' : Could not clone "file:///Q:/IT/Systems/Change-Control/Infrastructure/crom-rt01/"
ERROR: Cause: Error performing command: C:\Program Files (x86)\Git\bin\git.exe clone -o origin "file:///Q:/IT/Systems/Change-Control/Infrastructure/crom-rt01/" C:\Program Files (x86)\Jenkins\jobs\test 1\workspace
Command "C:\Program Files (x86)\Git\bin\git.exe clone -o origin "file:///Q:/IT/Systems/Change-Control/Infrastructure/crom-rt01/" C:\Program Files (x86)\Jenkins\jobs\test 1\workspace" returned status code 128: Cloning into C:\Program Files (x86)\Jenkins\jobs\test 1\workspace...
fatal: 'Q:/IT/Systems/Change-Control/Infrastructure/crom-rt01' does not appear to be a git repository
fatal: The remote end hung up unexpectedly

Trying next repository
ERROR: Could not clone repository
FATAL: Could not clone
hudson.plugins.git.GitException: Could not clone
at hudson.plugins.git.GitSCM$2.invoke(GitSCM.java:880)
at hudson.plugins.git.GitSCM$2.invoke(GitSCM.java:812)
at hudson.FilePath.act(FilePath.java:756)
at hudson.FilePath.act(FilePath.java:738)
at hudson.plugins.git.GitSCM.checkout(GitSCM.java:812)
at hudson.model.AbstractProject.checkout(AbstractProject.java:1181)
at hudson.model.AbstractBuild$AbstractRunner.checkout(AbstractBuild.java:536)
at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:424)
at hudson.model.Run.run(Run.java:1374)
at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:145)

Success from Windows shell (note placement of quotation marks):

Q:\>"C:\Program Files (x86)\Git\bin\git.exe" clone -o origin "file:///Q:/IT/Systems/Change-Control/Infrastructure/crom-rt01/" "C:\Program Files (x86)\Jenkins\jobs\test 1\workspace"
Cloning into C:\Program Files (x86)\Jenkins\jobs\test 1\workspace...
remote: Counting objects: 30, done.
remote: Compressing objects: 100% (30/30), done.
remote: Total 30 (delta 14), reused 0 (delta 0)
Receiving objects: 100% (30/30), 9.28 MiB | 3.01 MiB/s, done.
Resolving deltas: 100% (14/14), done.