Hi,
So I installed portable version like you said and didn't' get the error after installation. But it's still the same problem.

UI doesn't load correctly, no player, can't play external music files either. On my previous W7 Work PC (with the same security), I had no problems.
Edit: Opened preferences, went to player then got this:

Error message:
MusicBee v3.3.7165.34284 (Win10.0), 22 okt 2019 14:24:
System.TypeInitializationException: Typinitieraren för #=z6e$J6m9fRGu8fsE3E7ApgKY= utlöste ett undantag. ---> System.ApplicationException: Unable to load 'c:\program files (x86)\musicbee\bass.dll'
vid #=zCMaSRNnJCqtBTKKZmRgg94M=.#=zqguruO4uX9nJhib3bQ==(String #=zH2COsxe3vUru)
vid #=z6e$J6m9fRGu8fsE3E7ApgKY=..cctor()
--- Slut på stackspårning för interna undantag ---
vid #=z6e$J6m9fRGu8fsE3E7ApgKY=.#=zvd_xwPfWTQgQit4n3A==()
vid #=zSy1VA8m52scTsGJHeV5brRI=.#=zT3lGnlSG9XmUE7M6iw==()
vid #=z7kipSOagcObKfQMCW6tTVkJd$$Lk.#=zrQ69476S0K4vaDsgiwlOyKY=(Object #=zySAfqQw=, EventArgs #=z2hFhQMw=)
vid #=zQng_bqUenNzGG4bhdhq2RJiPNBgf.#=zhcLTtCmQt5dD()
vid #=zQng_bqUenNzGG4bhdhq2RJiPNBgf.#=zymOzZ0dGe58y(Int32 #=zO3uKGTk=)
vid #=z7kipSOagcObKfQMCW6tTVkJd$$Lk..ctor()
vid #=z4uPK4Y8pdmJkXEGF9sosr2Y=.#=zFYOBuUjtlPPeLfZzlw==(Object #=zySAfqQw=, EventArgs #=z2hFhQMw=)
vid #=z78Euauk7vGCFW$hdm_2U0jI=.#=zwSjn3e_c0uwI(#=zTdDrcilXTlOO5kFfsi9FM9XP0xsm #=z2hFhQMw=)
vid #=z78Euauk7vGCFW$hdm_2U0jI=.#=zVCsVI5Gvj0yL.#=zZUAnX_2sOnTX(Int32 #=zJp8qAqc=, Boolean #=z$a4W3NFVeMlD, Boolean #=znDcNw$z_CVSt)
vid #=z78Euauk7vGCFW$hdm_2U0jI=.#=zVCsVI5Gvj0yL.#=zjzXClMt$R0H6e_THRw==(Int32 #=zJp8qAqc=, Keys #=znpBAe7o=)
vid #=z78Euauk7vGCFW$hdm_2U0jI=.#=zVCsVI5Gvj0yL.OnMouseDown(MouseEventArgs #=z2hFhQMw=)
vid System.Windows.Forms.Control.WmMouseDown(Message& m, MouseButtons button, Int32 clicks)
vid System.Windows.Forms.Control.WndProc(Message& m)
vid #=zk$vucnNFkoRog0UZZ3lvjpQ=.WndProc(Message& #=zgyjfhZ0=)
vid System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
vid System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
vid System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)