OK, so I must admit it is sometime since I produced my last BluRay disc as I am now working in 4K.
However, just to confirm the process I was using early 2020.
I edited all the video in Premiere Pro (I think last version of 13.1.5) or early 14.x as mentioned below in previous comments.
Exported the timeline with the BluRay H264 HD preset in Premiere which gives the separate Audio and Video tracks for BluRay (not muxed together).
Then import that video transcode (as required) into Encore into respective Timelines as required.
When the authoring process in Encore is finished and it all plays OK from your menu structure and no build errors detected I export the project as a BluRay Disc ISO Image file.
Then using a burn utility ( Windows 10 now has this) but I used IMG Burn, burn the ISO image file to your BluRay disc.
I had success with this method with very few bad discs.
Certainly don't use Encore to Transcode files - you'll be there all day !.
You don't mention if you have the latest Creative Cloud but exporting H264 based video from Premiere now using Hardware such as NVidia Card and Intel Graphics GPU is very fast.

Yes, clients still want disks (DVD & Blu-ray). I've loved capabilities of Encore since the beginning and, although lots of workarounds have been required... continue to use it.

Up until recently, I was able to render DVD/BR files in ME and "Locate Transcoded File" to avoid slowness of Encore transcoding (doesn't use multi-core, etc.). SOMETHING HAS CHANGED!

Encore is still okay w/the ME DVD files, but Blu-ray is broken. No matter what, Encore will transcode (takes days). I've tried a variety of variations of MP4 and MPEG Blu-ray from ME... Encore doesn't like them and forces transcode.

If anyone has a workaround for this, I'm willing to pay!

Correct .... Encore is now end of life - but for those of use who purchased a Full Retail DVD with CS6 software on it all those years ago - it is still possible to load it on your own PC.
It was released before Windows 10 was around - hence the comments about running it in Windows 7 compatibility mode.
As we all know there is no more support on Encore so the discussion here just focuses on how latest Blu Ray encoded files from Premiere Pro/AME presets will work (or not work) with this legacy product.
The rationale behind my original post was why some BluRay encoded files from Premiere Pro/AME would not work with Encore. The BluRay Presets should comply with standards for MPEG2/MPEG4-AVC H264 Blu Ray encoding.

But there is no more Encore... ?

Final update from me on this - I just checked the last BluRay files I created, these were a year ago.
I am now using 4K video so only creating 4K H264 or H265 masters and streaming those on my own network server. I'm sure I will still have a need to dreate the odd BluRay disc in the future though for HD work.
My last BluRay HD files were created by the early release of Media Encoder V14.x I think using H264 BluRay presets and these worked OK with Encore 6 (6.0.2) - running in Windows 7 Compatibility mode only.

The only work around that I've found using windows 10 is to have Media Encoder create a high quality H264, you can use the YouTube1080p Full HD preset, and bring that into Encore and let Encore do the blu-ray encoding. I then have Encore make a disc image and use ImgBurn software to burn the blu-ray. A little clunky but it works.

Regarding comment below about Premiere 2020 H264 bluRay export - not tried this yet but Premiere 2019 (13.1.5) exports work but you have to run Encore.exe as windows 7 compatibility and run as administrator as well. In my opinion the chances of Adobe fixing anything to do with BluRay issues in future are zero. No interest shown in over 2 years.

I am now like many others unable to create an H.264 Bluray compatible file from Premiere Pro 2020 (v38) using the in-built presets. Like many other here a fix please Adobe or a refund

I have just clicked the "windows 7" compatibility....And it works.

Can Adobe Engineering or Product Management please advise if any changes have been made to AME in the last update version (13.1.3 - Build 45) relating to H264 Blu Ray Preset
Just for info I have just created a fairly large project (18GB) on Blu Ray using H264 Blu Ray Preset export via Premiere Pro (13.1.4 Build 1) which I assume uses AME engine.
The original problem is with Encore 6 and the Session Script issue.

With the latest version of AME and running Encore in Win 7 compatibility mode - and as Administrator the project built successfully
It would however be helpful for users do know what is going on as there has still been no feedback on this issue since I posted the original problem in Sept 2018.

Have engineering fixed it or not ?? - as my last Project Build worked.

Please can you break the radio silence and advise

Thanks

The only work-around I found was for PremierePro to export as QuickTime .MOV and not H264-BluRay or MPEG-BluRay. This also retains chapter markers.

Closing this one. It has been repeatedly ignored by Adobe , despite the fact some people still cannot get the project to build with Win 7 compatibility. Doesn't explain failures on MACs either.
After 9 months of wasted time with Adobe support. Move on.
...and they slept happily ever after.

Guys! I am having this same issue and DEFINITELY cannot have this happen right now, I happened to find a workaround that fixed this issue for me. If you right click Encore, properties, and change the compatibility mode to "Windows 7" that solved the issue for me, no more "failing to load the file."

Hope that helps!

So a global mail from Adobe Support telling me that Media Encoder 2017 (Version 11.1) would now infringe third party copyright issues implies this version (the last one to work for Blu Ray Preset encoding correctly) would be pulled.
[Did any of you posting here get such an email ? - dated 10th May 2019]

So far we have no comment or explanantion from Adobe Product Support Management on this issue whatsoever.
The whole scenario is puzzling - since many got Media Encoder version 2018/2019 version 13.x files to run in Encore 6 by running this is Windows 7 mode - which implied a Windows related issue in the later AME releases.

However, given this new statement from Adobe about Third Party IPR in Media Encoder 2017 (V 11.1) - it would suggest the later AME versions had different encoding software code entirely for AME 2018, 2019 etc to support Blu Ray Export??

As of May 2019 - This still leaves users without a stable solution and what seems difficult is to communicate the fact to Adobe Product Management heads is that Blu Ray encoding is still widely used.

If it can't be fixed - then the proposal to Adobe AME team is to source another third party solution house for Blu Ray encoding within AME future versions ....

Rather than continue this thread - can we get some positive response from AME team please.
This is what this Forum is designed for - correct ?

Just encountered this issue. Always reassuring when you find a thread of people with the same problem and no response from devs...

I thought I would add some new comments on this issue. I was surprised to see this is also affecting Mac users so the Windows 7 or 10 issue doesn't apply ??. I was also called by an Adobe customer service advisor last week who assured me that there were 'thousands of fixes' in 13.1 version and the BluRay H264 issue had 'probably' been fixed in the latest release. Sadly, it does not appear to be the case.
The other useful info someone posted was to download the TMPGEnc plug in - which has a separate H264 encoder with the BluRay H264 option - but that will cost you money which is not really acceptable when you are paying your monthly Creative Cloud fee.

Adobe - >> we are still waiting for your response months later ?.

This is the error in Encore on my Mac from Blu-Ray files encoded with AME 2018 and above:

Blu-ray Error: “device error”, Code: “3”, Note: “file can not open.(/Desktop/BLUTEST/encore/UntitledAuthorScriptHDMVSessions/Blutest.m4v._ves) -

Super fun!!!

Same issue here, please fix.

Truly unbelievable that this issue is not being addressed. Please Adobe, fix this. Still broken in the April AME 13.1 release.

come on Adobe - fix this! Still broken with premiere CC 2019 on Mac (13.03 Build 9) and AME 13.02 (Build 39)