If I have Sigil open, but don't use it for a few hours, I regularly get a message 'Sigil has encountered a problem. Sigil may need to close.
Error info: Critical: ARB::createContext: wglCreateContextAttribsARB() failed (GL error code: 0x502) for format: QSurfaceFormat(version 2.0, options QFlags<QSurfaceFormat::FormatOption>(), depthBufferSize 24, redBufferSize -1, greenBufferSize -1, blueBufferSize -1, alphaBufferSize -1, stencilBufferSize 8, samples 0, swapBehavior QSurfaceFormat:
efaultSwapBehavior, swapInterval 1, colorSpace QSurfaceFormat:
efaultColorSpace, profile QSurfaceFormat::NoProfile), shared context: 0x30000 (The operation completed successfully.)
Sigil version: 1.9.30
Runtime Qt: 5.12.9
Compiled Qt: 5.12.9
System: Windows 10 (10.0)
Architecture: x86_64
and another error box:
Error info: Critical: GDI::createContext: wglCreateContext failed. (Unknown error 0xc007001f.)
Sigil version: 1.9.30
Runtime Qt: 5.12.9
Compiled Qt: 5.12.9
System: Windows 10 (10.0)
Architecture: x86_64
and a third box:
Error info: Fatal: Failed to create OpenGL context for format QSurfaceFormat(version 2.0, options QFlags<QSurfaceFormat::FormatOption>(), depthBufferSize 24, redBufferSize -1, greenBufferSize -1, blueBufferSize -1, alphaBufferSize -1, stencilBufferSize 8, samples 0, swapBehavior QSurfaceFormat:
efaultSwapBehavior, swapInterval 1, colorSpace QSurfaceFormat:
efaultColorSpace, profile QSurfaceFormat::NoProfile) .
This is most likely caused by not having the necessary graphics drivers installed.
Install a driver providing OpenGL 2.0 or higher, or, if this is not possible, make sure the ANGLE Open GL ES 2.0 emulation libraries (libEGL.dll, libGLESv2.dll and d3dcompiler_*.dll) are available in the application executable's directory or in a location listed in PATH.
Sigil version: 1.9.30
Runtime Qt: 5.12.9
Compiled Qt: 5.12.9
System: Windows 10 (10.0)
Architecture: x86_64
If I am using Sigil, I have no such problems. I am accessing the machine through Remote desktop, so there is no user activity whatever for a few hours. AFAIK my system and drivers are up to date.