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Starting application via QtCreator makes it very slow (in Qt5.4.1, was not the case in Qt 5.1.1)

  • Hello,

    I am running Qt5.4.1 on Windows with MinGW. I have a strange thing happening with my application: when I start it (by pressing the play button) in Qt Creator (from Qt 5.4.1), the application starts correctly and behaves correctly, but is super slow (it is an openGl application, rendering takes ages it seems). When I manually launch my application (i.e. run the built executable), then speed is normal (i.e. very fast).
    I didn't have this strange behaviour with QtCreator from Qt 5.1.1.

    What I however already had with Qt 5.1.1 version: when my application is started from Skype, or Firefox (e.g. after a download), then the application also runs very slow.

    So I guess this is not directly a Qt problem, but more linked to the way a application is launched. Would someone happen to know what might be happening? Has the way how an application is launched in QtCreator changed?

    Thanks fro any insight!

  • Moderators


    What happens if you temporarily disable your antivirus?

  • I was thinking the same thing. I have seen antivirus software slow down applications to a crawl if there is any hint they are suspicious.

  • Thanks to the both of you. Disabling the antivirus din't help. Maybe some other background application?

  • Hi, a guess but maybe it's network related, for example, are you using a VPN or a proxyserver?
    Also are you on Win7 or 8.x? (because Qt Creator launches your app differently on Win7 vs. 8)

  • Thank you hskoglund,

    I am not using any of those. I am working on Windows 8.x
    Can I modify the way QtCreator launches my application? (i.e. without having to recompile it myself)

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