Sigil can't open my Epub file

[Siegfried]

Hello,

I just finished creating a Fixed Layout Epub in Adobe InDesign 2020. When reviewing it in SumatraPDF, there are a number of issues with it, so I thought I'd try to open it in Sigil and see if I can find out the problems through there.

The thing is, Sigil isn't able to open my file. I get the following message:

Error info: Cannot load file D:/My_Documents/ComicScripts/1 - WotN Arrival/WotN1_Complete.epub: ..\..\..\main_code\src\Sigil\Misc\Utility.cpp(240) : Throw in function class QString __cdecl Utility::ReadUnicodeTextFile(const class QString &)
Dynamic exception type: class boost::exception_detail::clone_impl<struct CannotOpenFile>
std::exception::what: Unknown exception
[struct file_errorstring *] = The system cannot find the path specified.
[struct file_fullpath *] = C:/Users/SILVER~1/AppData/Local/Temp/Sigil/scratchpad/2aa2f5b3-cc87-4016-b2d4-e9c438eaf10d/OEBPS/

Sigil version: 0.4.0
Runtime Qt: 4.7.2
Compiled Qt: 4.7.2
Platform: Windows SysInfo ID 240

Is there any reason Sigil can't open this file? It has no problems opening the other Epubs I have. However, those older Epubs were converted using InDesign CS6, but you'd think the newer Indesign 2020 would have less problems.

Hope someone can help me figure this out; I have enough problems with this file without Sigil doing this.

Thanks in advance.

[KevinH]

Sigil version 0.4.0 is so very old (from 2011?). It is no longer supported. Current versions are at Sigil 1.2.0 or later. Please try again with a more recent version of Sigil (say >= Sigil 0.9.14).

[DiapDealer]

I saw "Boost" in the error message and my mind nearly exploded.