Hmm, which OS version are you using? Which GPUs do you have in the system? Also, can you post what is shown when you click "Details" on this issue? Also, if you reboot your PC, does the issue persist?
Windows 10, 2x Raedon 5450.
Debug:
See the end of this message for details on invoking
just-in-time (JIT) debugging instead of this dialog box.
************** Exception Text **************
System.NullReferenceException: Object reference not set to an instance of an object.
at NiceHashMiner.sgminer.QueryCDevs()
at NiceHashMiner.sgminer..ctor()
at NiceHashMiner.Form1.StartupTimer_Tick(Object sender, EventArgs e)
at System.Windows.Forms.Timer.OnTick(EventArgs e)
at System.Windows.Forms.Timer.TimerNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
************** Loaded Assemblies **************
mscorlib
Assembly Version: 2.0.0.0
Win32 Version: 2.0.50727.8662 (QFE.050727-8600)
CodeBase: file:///C:/Windows/Microsoft.NET/Framework/v2.0.50727/mscorlib.dll
----------------------------------------
NiceHashMiner
Assembly Version: 1.2.2.0
Win32 Version: 1.2.2.0
CodeBase: file:///C:/Users/Admin/Downloads/NiceHashMiner_v1.2.2.0/NiceHashMiner.exe
----------------------------------------
System.Windows.Forms
Assembly Version: 2.0.0.0
Win32 Version: 2.0.50727.8662 (QFE.050727-8600)
CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Windows.Forms/2.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
----------------------------------------
System
Assembly Version: 2.0.0.0
Win32 Version: 2.0.50727.8662 (QFE.050727-8600)
CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System/2.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
System.Drawing
Assembly Version: 2.0.0.0
Win32 Version: 2.0.50727.8663 (QFE.050727-8600)
CodeBase: file:///C:/WINDOWS/assembly/GAC_MSIL/System.Drawing/2.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
----------------------------------------