Most Valuable Professional
Group: Forum Members
The identical entries at the bottom indicate the problem. ImageX.exe is a Microsoft tool that's used for creating WIM files, which are essentially image file containers from which one can boot a WinPE environment (and also store a Windows image that will be installed onto a PC). When Reflect builds Rescue Media, it assembles the various required files (WinPE, additional drivers, Reflect files, etc.) and uses ImageX to roll all of that up into a WIM file. The error is indicating that ImageX.exe isn't being found for the final phase of unmounting a mounted image in order to save everything into that WIM file, which suggests that some other process, likely anti-virus, deleted it. The other user who had this issue running ESET anti-virus had a similar error in his log, but it pertained to a file called Bootsect.exe, which is used in order to modify a partition's boot code. That can certainly be used for malicious purposes, but I'm surprised to find ImageX getting flagged since it's not nearly as dangerous and it's also been around since the Vista days, in fact Microsoft has even replaced most of its functionality with a new tool called DISM that was itself introduced many years ago (though ImageX still works perfectly well for many uses and continues to exist because it can do some things that DISM can't.)
Anyhow, this reinforces my theory that AV is your culprit here. You could maybe try adding "C:\ProgramData\Macrium\Reflect" to your exclusions list.