# ngsolve deinstallation confuses cmake on Windows 10
**URL:** https://discourse.cmake.org/t/ngsolve-deinstallation-confuses-cmake-on-windows-10/6758
**Category:** Usage
**Created:** [October 30, 2022, 10:32am UTC](https://discourse.cmake.org/t/ngsolve-deinstallation-confuses-cmake-on-windows-10/6758 "2022-10-30T10:32:03Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@Kai](https://discourse.cmake.org/u/Kai)
#### Post date: [October 30, 2022, 10:32am UTC](https://discourse.cmake.org/t/ngsolve-deinstallation-confuses-cmake-on-windows-10/6758/1 "2022-10-30T10:32:03Z")
Hi Guys,
there is a weird behavior on Windows 10 after uninstalling some old version of ngsolve (ngsolve-v6.2.2104).
If i want to compile some C++ program, that is not ngsolve related, in the linking stage zlib.lib is not found any more. Until now i did not need to handle zlib.lib in any way. To solve the problem i tried to download zlib from GnuWin32 on sourceforge and set ZLIB\_LIBRARY and ZLIB\_INCLUDE\_DIR.
the error message reads
Code:
LINK : fatal error LNK1104: Datei “C:\Program Files\ngsolve-v6.2.2104\Lib\zlib.lib”
i am out of ideas, please help ! 🙂
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### Author:  [@ben.boeckel](https://discourse.cmake.org/u/ben.boeckel)
#### Post date: [October 30, 2022, 3:43pm UTC](https://discourse.cmake.org/t/ngsolve-deinstallation-confuses-cmake-on-windows-10/6758/2 "2022-10-30T15:43:31Z")
It seems that “some C++ program” is using zlib and happened to find the ngsolve copy? You’ll need to get a different zlib to compile against.
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### Author:  [@Kai](https://discourse.cmake.org/u/Kai)
#### Post date: [November 2, 2022, 7:44am UTC](https://discourse.cmake.org/t/ngsolve-deinstallation-confuses-cmake-on-windows-10/6758/3 "2022-11-02T07:44:50Z")
If “some C++ program” uses zlib, then implicitly. It uses a bunch of libraries, Qt or assimp i.e., but not ngsolve. To solve the problem i tried to download zlib from GnuWin32 on sourceforge and set ZLIB\_LIBRARY and ZLIB\_INCLUDE\_DIR. But the problem further consists.
It is also confusing that it referes to ngsolve-v6.2.2104 not ngsolve-v6.2.2204. I uninstalled ngsolve-v6.2.2104 and installed ngsolve-v6.2.2204, this is the event the problem occures.
So it is not a problem of “missing” zlib i think, zlib is present at least in ngsolve-v6.2.2204 but also Qt or assimp ship with some copy i know. It is a reference problem …
I also asked in the ngsolve forum but no solution until now, and since it is very cmake specific in my point of view i hoped to get some knowledge about how cmake looks up for libs on windows …
even the global and user specific path variables did not contain any reference to ngsolve-v6.2.2104 …
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### Author:  [@Kai](https://discourse.cmake.org/u/Kai)
#### Post date: [November 2, 2022, 7:45am UTC](https://discourse.cmake.org/t/ngsolve-deinstallation-confuses-cmake-on-windows-10/6758/4 "2022-11-02T07:45:39Z")
may be it helpes to uninstall/install cmake ?
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### Author:  [@ChrisJaquet](https://discourse.cmake.org/u/ChrisJaquet)
#### Post date: [November 2, 2022, 7:49am UTC](https://discourse.cmake.org/t/ngsolve-deinstallation-confuses-cmake-on-windows-10/6758/5 "2022-11-02T07:49:32Z")
It sounds like a cached variable has not been updated. Have you deleted the CMakeCache (after removing ngsolve and installing the gnuwin32 version of zlib) and tried running CMake again?
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### Author:  [@Kai](https://discourse.cmake.org/u/Kai)
#### Post date: [November 2, 2022, 9:07am UTC](https://discourse.cmake.org/t/ngsolve-deinstallation-confuses-cmake-on-windows-10/6758/6 "2022-11-02T09:07:13Z")
Yes, i deleted the whole build folder and do configure/generate cmake command