If an file name is used, which is obviously invalid for some operations,
the following can happen:
1. The file gets opened anyway, although an error message states
otherwise:
 - File exists, but cannot be read
 - File mode specification error: (file-error Unlocking file Invalid argument //collaboration.dummyname.com@SSL/DavWWWRoot/subjects/foo bar.docx)
2. Trying to close the buffer triggers simmilar errors
3. Trying to exit emacs leads to a question wheter the file shall be saved.
 - Selecing No now again leads to similar error message, but now emacs also freezes (is unresponsive and GUI is no longer updated).
 - Emacs must be killed via task-manager.

In GNU Emacs 28.0.50 (build 1, x86_64-w64-mingw32)
 of 2020-07-05 built on CIRROCUMULUS
Repository revision: e3ada2063aa286ea6898a60d95061a77fb752ca8
Repository branch: master
Windowing system distributor 'Microsoft Corp.', version 10.0.18363
System Description: Microsoft Windows 10 Pro (v10.0.1909.18363.1316)
Recent messages:
Parsing archive file...done.
File mode specification error: (file-error Unlocking file Invalid argument //collaboration.dummyname.com@SSL/DavWWWRoot/subjects/foo bar.docx)
next-line: End of buffer
Beginning of buffer [5 times]
Mark set
End of buffer [2 times]
Beginning of buffer [2 times]
Buffer SPLF3_ChangeDocumentation_V3.4.1.27_to_V3.5.X.Y.docx modified; kill anyway? (y or n) y
kill-current-buffer: Unlocking file: Invalid argument, //collaboration.dummyname.com@SSL/DavWWWRoot/subjects/foo bar.docx
Beginning of buffer [3 times]
Configured using:
 'configure --without-dbus --host=x86_64-w64-mingw32
 --without-compress-install -C 'CFLAGS=-O2 -static -g3'
 host_alias=x86_64-w64-mingw32 PKG_CONFIG_PATH=/mingw64/lib/pkgconfig'
Configured features:
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HARFBUZZ ZLIB TOOLKIT_SCROLL_BARS MODULES THREADS JSON PDUMPER LCMS2 GMP
Important settings:
 value of $LANG: DEU
 locale-coding-system: cp1252
Major mode: Zip-Archive
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 global-edit-server-edit-mode: t
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 helm-mode: t
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 company-mode: t
 global-magit-file-mode: t
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 magit-wip-after-apply-mode: t
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 display-battery-mode: t
 delete-selection-mode: t
 shell-dirtrack-mode: t
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 global-font-lock-mode: t
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 auto-composition-mode: t
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 column-number-mode: t
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 global-visual-line-mode: t
 visual-line-mode: t
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Load-path shadows:
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d:/home/.emacs.d/vendor/cursor-chg/cursor-chg hides d:/home/.emacs.d/elpa/cursor-chg-20170221.1610/cursor-chg
d:/home/.emacs.d/elisp/git/git hides d:/home/.emacs.d/elpa/git-20140128.1041/git
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emacs)
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