A better way to debug MDL loader error 127

RE: A better way to debug MDL loader error 127

MaryB — Thu, 07 Apr 2022 15:33:49 GMT

FYI

While this is probably not the source of your issue, you should be aware that SS4 is not certified to run on Windows 10, nor Windows 11. It might run fine, but there is definitely the possibility of some things not working. SS4 is also no longer supported by Bentley, so you will be essentially on your own when troubleshooting any issues stemming from that.

RE: A better way to debug MDL loader error 127

Jan Šlegr — Thu, 07 Apr 2022 06:06:29 GMT

[quote userid="1070775" url="~/products/administration/f/product-administration-forum/227981/a-better-way-to-debug-mdl-loader-error-127/705272"]I thought editing MS_ADDINDEPENDENCYPATH will help (like it will use this folder as priority for DLL lookup) but for some reason it wasn't used[/quote]

Good to know you solved the issue :-)

I remember (not too well) this vairable and general problem of dll location was discussed in the past, but I guess there was no conclusion done at this time.

Regards,

Jan

RE: A better way to debug MDL loader error 127

Lubo B — Wed, 06 Apr 2022 18:38:14 GMT

I managed to fix it using Process Monitor logs. I saw that MS tried to load one of my dependencies from different folder than I wanted, causing this trouble. I thought editing MS_ADDINDEPENDENCYPATH will help (like it will use this folder as priority for DLL lookup) but for some reason it wasn't used, so i had to edit the priority of my folder in environment variable Path(basically forcing the right folder to be used first).

RE: A better way to debug MDL loader error 127

Jan Šlegr — Tue, 05 Apr 2022 10:33:44 GMT

[quote userid="1070775" url="~/products/administration/f/product-administration-forum/227981/a-better-way-to-debug-mdl-loader-error-127/704971"]but it looked fine[/quote]

DependencyWalker tells only what is configured in the file itself, not whether it was found or not. Plus, it!s a tree, so directly linked libraries can require other files...

To ensure the same workspace can also help, because there are variables defining where to find .ma files and dependency dll files.

Regards,

Jan

RE: A better way to debug MDL loader error 127

Lubo B — Tue, 05 Apr 2022 10:00:45 GMT

Its plugin .ma consisting also of DLL. I sent DependencyWalker app to client and asked them to send me a screenshot, but it looked fine(even though as u said, its kinda tricky when DLLs are not in same folder). I hope Process Monitor log will tell me more.

[quote userid="2473" url="~/products/administration/f/product-administration-forum/227981/a-better-way-to-debug-mdl-loader-error-127/704966"]Are versions (MicroStation, Windows as well) the same?[/quote]

Well actually i havent thought about Windows version. Because i didn't try it on windows 11 yet.

RE: A better way to debug MDL loader error 127

Jan Šlegr — Tue, 05 Apr 2022 09:42:31 GMT

One more idea:

[quote userid="1070775" url="~/products/administration/f/product-administration-forum/227981/a-better-way-to-debug-mdl-loader-error-127"]MDL loader error "OS could not load xx.dll" (error 127) [/quote]

If the application is native code application, I recommend to check all expected depdencies. Some "dependency walker" (like this one) can help to analyze whether all necessary dll (libraries) are available. But what can be tricky is when dlls are in different folders and MicroStation or Windows setting is involved in the dependency resolution.

Regards,

Jan

RE: A better way to debug MDL loader error 127

Jan Šlegr — Tue, 05 Apr 2022 09:37:23 GMT

[quote userid="1070775" url="~/products/administration/f/product-administration-forum/227981/a-better-way-to-debug-mdl-loader-error-127/704960"]Hello, this error is caused when I try to load my own plugin .ma file.[/quote]

Because "MDL" is too fuzzy term with several different meanings: What is "type" of .ma application? Is it old pseudocode application (no dll, only .ma + rsc files), or is it native application (.ma loader + dll files)?

[quote userid="1070775" url="~/products/administration/f/product-administration-forum/227981/a-better-way-to-debug-mdl-loader-error-127/704960"]I mean, the plugin works on other machines but this is a new clean install machine which displays the error[/quote]

Are versions (MicroStation, Windows as well) the same?

Often, even when probably not this case, different behavior is caused by missing libraries (like C runtime / msvcrt.dll).

[quote userid="1070775" url="~/products/administration/f/product-administration-forum/227981/a-better-way-to-debug-mdl-loader-error-127/704960"]Thats why some more accurate log would come in handy in these situations.[/quote]

The problem is that it's internal MicroStation error, not Windows one. Maybe to use debugger (e.g. WinDbg) and to attach to the process, can be tried.

With regards,

Jan

RE: A better way to debug MDL loader error 127

Lubo B — Tue, 05 Apr 2022 09:07:54 GMT

Hello, this error is caused when I try to load my own plugin .ma file. The error displays at the start of the microstation. Yes, it appears in console window (so thats why i was wondering if MS keeps some kind of logs which could describe it more properly). Version of MS is kinda old one, MicroStation V8i SS4 08.11.09.867. I mean, the plugin works on other machines but this is a new clean install machine which displays the error, and as I dont have access to the machine its kinda troublesome to troubleshoot this problem. Thats why some more accurate log would come in handy in these situations. I thought reinstall of MS would help but it didn't.

RE: A better way to debug MDL loader error 127

Marc Thomas — Tue, 05 Apr 2022 08:25:10 GMT

Hi Lubo, this is likely to be a version mismatch between the MDL and MicroStation.

Which MDL is involved (or is it more than one)?

When do you see the error?

I'm assuming this is appearing in a black text window?

Which version of MicroStation?