sometimes apt leaves behind o4w_env.bat.tmpl in %osgeo4w_root%. I've not been able to track down when/why, but it may be when an apt command fails (upgrade, remove) because in-use files such as msvcr71.dll can't be acted in (part of pkg-shell).
(In [1182]) apt: finally realised the simplest way to deal with leftover .tmpl files is to not remove their name from the install manifest :) Closes #224.
(In [1182]) apt: finally realised the simplest way to deal with leftover .tmpl files is to not remove their name from the install manifest :) Closes #224.