I once had report similar to that. (with the assumption that GPT had anything to do with it), but I couldn't reproduce the problem.
It worked at my place with a GPT layout drive.

Which version (update) of windows 10 are you on ?

Windows 10 21H1

Maybe it's on the motherboard?
It's the Asus ROG STRIX Z590-E Gaming.
VT-X is enable.

Today I just starting having the same problem. I'm using Windows 10 Pro, 64bit ver 21H1, with an Asus ROG Maximus XI Hero (WiFi) MB and an Asus 2080s GPU. Dosbox 0.74-3 was working fine 2-3 weeks ago and has worked flawlessly for years. Now it starts and then closes after trying to execute the .conf file. No error messages. stderr.txt is blank. stderr.txt also remains blank when launching dosbox with -noconsol. Changing output= to all options did not help. Trying the default .conf and other various configurations of .conf did not help. Share is off in GeForce Experience. I noticed it worked normally in safe mode so I tried inhibiting the apps in apps startup. I had mixed results. With all startup apps off, it worked but wasn't repeatable. In trying to troubleshoot which apps, but eventually getting back to all apps off, Dosbox failed to start. Earlier versions of Dosbox that I installed today failed the same way. Yet I have a second computer running the same version of Windows and Dosbox on an Intel DP45SG MB with a Radeon HD6870 GPU and Dosbox works flawlessly. Any thoughts? Is there a way to record errors or execution progress?

Hmm, the update to 21H1 seems to be optional at this time. Anyone NOT having the problem after updating?

I have Windows 21H1 x64 running on my Dell M4800 laptop with 17 4810MQ CPU and DOSBox 0.74.3 starts up just fine

EDIT : Secure boot is enabled

Note my second computer (DP45SG MB, Intel quad core2) is running 21H1 x64, does not have secure boot and is running Dosbox 0.74-3 just fine.

Does GeForce Experience seem to be a common factor in the problem cases? It has been known to cause a variety of problems with DOSBox, particularly its overlay feature needed to display framerate, but perhaps depending on the output= setting in DOSBox.

Execute DOSBox from here or wherever you installed it but use the -noconsole switch
C:\Program Files (x86)\DOSBox-0.74-3\dosbox.exe -noconsole

Go here and paste the contents of stdout.txt in this thread (if DOSBox is installed in a different location then go to that location in virtualstore)
%localappdata%\VirtualStore\Program Files (x86)\DOSBox-0.74-3

Both stdout.txt and stderr.txt are blank after running dosbox.exe -noconsole

Antivirus or Antimalware springs to mind . Temporarily disabling any third party ones might be a good test .

Also check Windows event logs . They may contain useful hints .

Virus scanner on or off does not make a difference
Event Viewer shows the Dosbox fault and lists AudioDevProps2.dll, ver 2.6.4.0 from Sonic Studio III as the faulting module. My other computer (DP45SG) does not have Sonic Studio III.
I need to go out for a bit and will look at this on my return

As far as I can see now, it is due to my Windows 10 installation.

I reinstalled Windows 10 on an empty SSD. Everything runs.

Maybe an installed program is causing the problems, or a setting in Windows itself.

I will reinstall everything the days and test after each step.

Thank you for your help.

Nitro

Alot of those shitty additional programs with drivers always cause issues for me so likely what it was.

Sonic Studio seems to break other stuff too, at least for some people .
Removing that DLL seems to fix it (to a point), whether or not it breaks Sonic Studio and, if it does, to what point, I do not know .

Based on https://www.asus.com/microsite/mb/rog-supreme … nic_studio.html , I would guess that the DLL in question is linked to some kind of virtual audio device used to enable audio capture while streaming . From what I can tell, the issue seems linked to an interaction between Sonic Studio and a recent Windows update .

See :

https://www.reddit.com/r/techsupport/comments … evprops2dll_is/

https://forums.pcgamer.com/threads/several-ga … ate#post-233374

I uninstalled Sonic Studio 3 and Dosbox immediately started working normally. After rebooting and playing around, Dosbox continued to work properly. I tried to reinstall Sonic Studio (latest from Asus website) but the installation now violates some kind of new windows security measure and simply terminates. Perhaps this is related to the Dosbox issue and the various other issues darry points to. Clearly a few weeks ago Dosbox worked fine in the presence of Sonic Studio and neither have been updated. So I also suspect one of the weekly windows security updates caused the problem. I'm sure eventually the 3rd party developers will catch up with their own updates.
It looks like Sonic Studio 3 and Sonic Radar 3 are a suite provided by A-Volute and bundled with the Realtek audio driver distributed by Asus for their MB's. Both Sonic Radar and Sonic Studio have beautiful graphics but since I don't stream or capture streaming audio, I have never found a use for them. Likely I will simply go on without the Sonic Suite until I see an update.
Thanks darry for pointing me to Event Viewer.

Patp01 wrote on 2021-07-28, 01:38:

I uninstalled Sonic Studio 3 and Dosbox immediately started working normally. After rebooting and playing around, Dosbox continued to work properly. I tried to reinstall Sonic Studio (latest from Asus website) but the installation now violates some kind of new windows security measure and simply terminates. Perhaps this is related to the Dosbox issue and the various other issues darry points to. Clearly a few weeks ago Dosbox worked fine in the presence of Sonic Studio and neither have been updated. So I also suspect one of the weekly windows security updates caused the problem. I'm sure eventually the 3rd party developers will catch up with their own updates.
It looks like Sonic Studio 3 and Sonic Radar 3 are a suite provided by A-Volute and bundled with the Realtek audio driver distributed by Asus for their MB's. Both Sonic Radar and Sonic Studio have beautiful graphics but since I don't stream or capture streaming audio, I have never found a use for them. Likely I will simply go on without the Sonic Suite until I see an update.
Thanks darry for pointing me to Event Viewer.

I am happy that you found a solution . I personally install as little bundled software as I can when installing drivers, except if I can find information that convinces me the said software might potential be useful to me in some way . This has very rarely been the case .

Quick Update: There was an A-Volute driver update from Microsoft system updates yesterday. Don't know if it was related or not but now Sonic Radar and Sonic Studio from Asus's Realtek audio drivers install properly and semi-auto update through Microsoft Store. Sonic Suite and Dosbox are now working in harmony.