Why Windows font disappered after running my Qt application? - c++

Question

Background
I write an uninstaller on Windows platform using Qt and C++. When running, It copy itself to windows temp folder and rerun the exe in that folder. The new process of uninstaller will stop and uninstall some service & driver I installed, then remove some files on the disk.
Problem
After the uninstallation is complete, the font of the Windows system will disappeared partly, as following picture shows:
As you can see, the oringe one is my uninstaller, and both the font of folder name in windows File explorer and the font in my blue button is disappeared, but some other font is still visible like the left side nav bar.
And most important, it just happend by accident(But it really happened many times on some machines). It cannot reappear stably.
I can recover it by restart the File explorer.exe or reboot the Windows system.
Environment
I used a static lib of Qt 5.15.2 which I build from source.
C++ 17
All the executable is compiled and linked by microsoft visual studio(2019) c++ kits
All the application is linked statically with MT option.
I tested the uninstaller on Win7 & Win10 (The problem had appeared on both platforms).
The font which is used in my uninstaller is 'Alibaba PuHui' and 'Roboto'.
Qt font usage
I think the most possible reason is the wrong usage of the Qt font loading in my uninstaller, so I put the method I used here.
Firstly, I embed the font in my application through .qrc file
<RCC>
<qresource prefix="/">
<file>res/font/Alibaba-PuHuiTi-Medium.ttf</file>
<file>res/font/Alibaba-PuHuiTi-Regular.ttf</file>
<file>res/font/Roboto-Regular.ttf</file>
<file>res/font/Roboto-Medium.ttf</file>
</qresource>
</RCC>
Then I init the font by the initFont() function
#include <QString>
#include <QFontDatabase>
inline QString ali_font_regular = "";
inline QString ali_font_medium = "";
inline QString roboto_font_regular = "";
inline QString roboto_font_medium = "";
inline void initFont() {
int med_font_id = QFontDatabase::addApplicationFont(":/res/font/Alibaba-PuHuiTi-Medium.ttf");
ali_font_medium = QFontDatabase::applicationFontFamilies(med_font_id).at(0);
int reg_font_id = QFontDatabase::addApplicationFont(":/res/font/Alibaba-PuHuiTi-Regular.ttf");
ali_font_regular = QFontDatabase::applicationFontFamilies(reg_font_id).at(0);
int roboto_reg_font_id = QFontDatabase::addApplicationFont(":/res/font/Roboto-Regular.ttf");
roboto_font_regular = QFontDatabase::applicationFontFamilies(roboto_reg_font_id).at(0);
int roboto_medium_font_id = QFontDatabase::addApplicationFont(":/res/font/Roboto-Medium.ttf");
roboto_font_medium = QFontDatabase::applicationFontFamilies(roboto_medium_font_id).at(0);
}
And Finally, the font setting of my Qt widget is like this:
logo_text_b = new QLabel(this);
logo_text_b->setMargin(0);
logo_text_b->setText("test");
QFont f_b(ali_font_medium);
f_b.setPixelSize(12);
logo_text_b->setFont(f_b);
logo_text_b->setStyleSheet("QLabel { color : white; }");
I have no thoughts what causes it happend, And I can't find a way to debug because it happend by accident. I hope someone can give me some direction. THANKS!