Lost access to Windows home folder, possibly from untarring to it using cygwin

I had a whole bunch of configuration files stored in a zip file, spanning both my Windows 7 user file tree and my cygwin user file tree.

For example

drwx------+ 1 MyUserName Domain Users     0 Nov 24 15:21 c
drwx------+ 1 MyUserName Domain Users     0 Nov 24 15:21 c/Users
drwx------+ 1 MyUserName Domain Users     0 Nov 24 16:12 c/Users/MyUserName
drwx------+ 1 MyUserName Domain Users     0 Nov 24 16:34 c/Users/MyUserName/Documents
-rwxrwx---  1 MyUserName Domain Users 32464 Jul 28 17:41 c/Users/MyUserName/Documents/_viminfo
-rwxrwx---  1 MyUserName Domain Users 15092 Jul 27 13:42 c/Users/MyUserName/Documents/_vimrc
drwx------+ 1 MyUserName Domain Users     0 Nov 24 16:11 c/Users/MyUserName/Documents/vimfiles
-rwxrwx---  1 MyUserName Domain Users   315 Oct 15  2016 c/Users/MyUserName/Documents/vimfiles/.netrwhist
drwx------+ 1 MyUserName Domain Users     0 Nov 24 15:21 c/Users/MyUserName/Documents/vimfiles/after
drwx------+ 1 MyUserName Domain Users     0 Nov 24 15:21 c/Users/MyUserName/Documents/vimfiles/after/ftplugin
-rwxrwxr-x  1 MyUserName Domain Users    39 Feb  9  2016 c/Users/MyUserName/Documents/vimfiles/after/ftplugin/netrw.vim
drwx------+ 1 MyUserName Domain Users     0 Nov 24 15:21 c/Users/MyUserName/Documents/vimfiles/after/syntax
-rwxrwxr-x  1 MyUserName Domain Users    28 Jun 19  2013 c/Users/MyUserName/Documents/vimfiles/after/syntax/tex.vim
drwx------+ 1 MyUserName Domain Users     0 Nov 24 15:21 c/Users/MyUserName/Documents/vimfiles/colors
-rwxrwx---  1 MyUserName Domain Users  5006 May 27  2016 c/Users/MyUserName/Documents/vimfiles/colors/mine.vim
drwx------+ 1 MyUserName Domain Users     0 Nov 24 15:21 c/Users/MyUserName/Documents/vimfiles/plugin
-rwxrwxr-x  1 MyUserName Domain Users 26547 Sep 17  2014 c/Users/MyUserName/Documents/vimfiles/plugin/bufexplorer.vim
-rw-------  1 MyUserName Domain Users  3024 Jan 26  2015 c/Users/MyUserName/Documents/vimfiles/plugin/ChristiansHi20150126.vim
drwx------+ 1 MyUserName Domain Users     0 Nov 24 15:21 c/Users/MyUserName/Documents/vimfiles/spell
-rwxrwxr-x  1 MyUserName Domain Users   963 Sep  8  2014 c/Users/MyUserName/Documents/vimfiles/spell/en.latin1.add
drwx------+ 1 MyUserName Domain Users     0 Nov 24 15:21 c/Users/MyUserName/Documents/vimfiles/syntax
-rw-r--r--  1 MyUserName Domain Users  8870 Feb 13  2015 c/Users/MyUserName/Documents/vimfiles/syntax/asy.vim
-rwxrwxr-x  1 MyUserName Domain Users  2749 Jul 30  2013 c/Users/MyUserName/Documents/vimfiles/syntax/texmf.vim
-rwxrwxr-x  1 MyUserName Domain Users 33322 Jun  8  2011 c/Users/MyUserName/Documents/vimfiles/syntax/vbnet.vim
drwx------+ 1 MyUserName Domain Users     0 Nov 24 15:21 etc
-rwxrwx---  1 MyUserName Domain Users   518 Dec  4  2014 etc/fstab
-rw-r--r--  1 MyUserName Domain Users   192 Aug 19  2014 etc/fstab.cygwin64default
drwx------+ 1 MyUserName Domain Users     0 Nov 24 15:21 etc/fstab.d
-rwxrwx---  1 MyUserName Domain Users     0 Aug  4  2011 etc/fstab.d/SomeUserName
drwx------+ 1 MyUserName Domain Users     0 Nov 24 15:21 home
drwx------+ 1 MyUserName Domain Users     0 Nov 24 15:21 home/MyUserName
-rwx------  1 MyUserName Domain Users  1852 Aug 21 14:21 home/MyUserName/.alias.bash
-rwx------  1 MyUserName Domain Users  1503 Aug 19  2014 home/MyUserName/.alias.csh
lrwxrwxrwx  1 MyUserName Domain Users     7 Nov 24 15:21 home/MyUserName/.bash_login -> .bashrc
-rwxr-xr-x  1 MyUserName Domain Users  1150 Aug 19  2014 home/MyUserName/.bash_profile
-rwxr-xr-x  1 MyUserName Domain Users  2499 Jun 15  2015 home/MyUserName/.bashrc
-rwx------  1 MyUserName Domain Users  1904 Aug 19  2014 home/MyUserName/.cshrc
-rwxr-xr-x  1 MyUserName Domain Users    41 Aug 19  2014 home/MyUserName/.inputrc
-rw-r--r--  1 MyUserName Domain Users   101 Aug 19  2014 home/MyUserName/.minttyrc
-rwx------  1 MyUserName Domain Users   102 Jan 27  2015 home/MyUserName/.octaverc
-rwxr-xr-x  1 MyUserName Domain Users    65 Dec  2  2014 home/MyUserName/.pdfjam.conf
-rwxr-xr-x  1 MyUserName Domain Users   792 Aug 19  2014 home/MyUserName/.profile
-rw-------  1 MyUserName Domain Users    51 Jun 14  2015 home/MyUserName/.Renviron
-rw-------  1 MyUserName Domain Users   706 Apr 20  2015 home/MyUserName/.Rprofile
-rwx------  1 MyUserName Domain Users    58 Jun 16  2015 home/MyUserName/.startxwinrc
-rwx------  1 MyUserName Domain Users  9521 Aug 19  2014 home/MyUserName/.twmrc
-rwx------  1 MyUserName Domain Users  9306 Aug 19  2014 home/MyUserName/.twmrc.alt
-rwx------  1 MyUserName Domain Users  1803 May  1  2015 home/MyUserName/.Xresources
drwx------+ 1 MyUserName Domain Users     0 Nov 24 15:21 home/MyUserName/bin
-rwxrwx---  1 MyUserName Domain Users   138 May 14  2012 home/MyUserName/bin/a2pdf.bash
-rwxrwx---  1 MyUserName Domain Users     8 Jan 25  2014 home/MyUserName/bin/bc.rc
-rwxrwx---  1 MyUserName Domain Users    29 Jan 25  2014 home/MyUserName/bin/dosbc
-rw-------  1 MyUserName Domain Users  1557 Nov  8  2013 home/MyUserName/bin/dvi2pdfa
-rwxrwx---  1 MyUserName Domain Users   349 Aug  2  2013 home/MyUserName/bin/pcvim
drwx------+ 1 MyUserName Domain Users     0 Nov 24 15:21 usr
drwx------+ 1 MyUserName Domain Users     0 Nov 24 15:21 usr/share
drwx------+ 1 MyUserName Domain Users     0 Nov 24 16:11 usr/share/vim
lrwxrwxrwx  1 MyUserName Domain Users    35 Nov 24 15:21 usr/share/vim/vimfiles -> /c/Users/MyUserName/Documents/vimfiles
lrwxrwxrwx  1 MyUserName Domain Users    33 Nov 24 15:21 usr/share/vim/vimrc -> /c/Users/MyUserName/Documents/_vimrc

I unpacked everything into a temp folder, and copied them into their proper place issuing the following from the temp directory:

tar cf - * | ( cd / ; tar xf - )

I think I created a big problem. I suspect that all the unpacked directories overwrite the existing directories, and the ownership of the directories changed to SYSTEM, including c:\Users\MyUserName. Now I can't even browse to my own Windows home folder using Windows Explorer. That is, I can't start from c:\ and click my way down. I get a permission denied at c:\Users\MyUserName, apparently because the ownership changed:

$ls -ld /c/Users/MyUserName
drwx------+ 1 SYSTEM SYSTEM 0 2017-11-24 16:56 /c/Users/MyUserName

In contrast to the above, issuing cygstart MyUserName from /c/Users opens up the Windows home directory just fine, but it looks like the home directory of a virgin account, containing none of the things that I know should be there. Perhaps it is a sandbox version from the c:\users\MyUserName\Appdata\local\VirtualStore file tree.

Another possibility is that the permissions are messed up by the way that file systems are mounted via fstab:

# For a description of the file format, see the Users Guide
# http://cygwin.com/cygwin-ug-net/using.html#mount-table

# This is default anyway:
# none /cygdrive cygdrive binary,posix=0,user 0 0
c: /c ntfs binary,posix=0,user,auto
d: /d ntfs binary,posix=0,user,auto
e: /e ntfs binary,posix=0,user,auto
f: /f ntfs binary,posix=0,user,auto
g: /g ntfs binary,posix=0,user,auto
i: /i ntfs binary,posix=0,user,auto
o: /o ntfs binary,posix=0,user,auto
r: /r ntfs binary,posix=0,user,auto
s: /s ntfs binary,posix=0,user,auto

I'm not very familiar with the fine points of mounting file systems, so I'm not sure whether the above shows anything. My check is to circumvent /c using cygdrive, which still exhibits the same problem:

$ls /cygdrive/c/Users/MyUserName/
ls: cannot open directory /cygdrive/c/Users/MyUserName/: Permission denied

If I go to my IT folks with this weird permissions/security problem, they will probably chop off all my appendages, get me fired, and never again let me mess around with anything but Microsoft Office.

As a non-administrator, is there anything I can do to recover my normal access the c:\Users\MyUserName?

I'm not entirely sure that the problem is due to untarring to c:\Users\MyUserName, but its my only suspect right now. Due to long debilitating approval processes, I have a 2015 version of cygwin installed.