HOWTO: Run multiple instances of DAZ Studio 4.12

Published on 2019/10/16 by Igor Levicki

Starting with DAZ Studio Public Beta version 4.12.1.16, it is no longer possible to start multiple instances of the application. The official justification for this change is as follows:

Only a single instance of the application, per release channel, is now allowed to run at a time; attempts to load registered file types via double-click or "open with" commands will now forward to a running instance (if any) instead of allowing concurrent instances that compete for resources and cause conflicts.

Frankly, I have no idea whose bright idea that was, but judging by the user comments, not a single one of them seems to appreciate this change. Why? Because it is breaking their workflow, and because nobody ever asked for it.

Here is where my reverse-engineering skills come to the rescue -- by following the procedure below you too can re-enable old behavior and launch multiple instances of DAZ Studio.

Disclaimer:

The patching procedure applies only to DAZ Studio Public Beta 4.12.1.16 -- attempting to apply this patch to any other DAZ Studio version can lead to outcomes ranging from DAZ Studio simply crashing or not starting to seemingly working properly but silently corrupting your data.

Note:

This patch is only disabling detection of another running instance, but if you encounter any issue while using the program after applying the patch, please first restore the backed up file and re-test to see if you can still reproduce the issue. Only if the issue still persists with the original file you should proceed to submit a bug report to DAZ 3D developers.

If your DAZ Studio is running, close it.
Download Swiss File Knife. Swiss File Knife is a command-line tool you will use to modify DAZ Studio.
Right-click on downloaded sfk.exe file, select Properties, check the Unblock box, then click Apply.
Copy sfk.exe to your C:\Windows\System32 folder.
Navigate to C:\Program Files\DAZ 3D\DAZStudio4 Public Build and make a backup copy of DzCore.dll.
Launch Command Prompt as Administrator.

In Command Prompt window type the following command:

cd C:\Program Files\DAZ 3D\DAZStudio4 Public Build

After you press Enter it should read:

C:\Program Files\DAZ 3D\DAZStudio4 Public Build>

In Command Prompt window type the following command:
```
sfk setbytes DzCore.dll 0xB6C9FC 0x33 -yes
```
After you press Enter it should read:
```
1 bytes written.
```
If you are typing instead of copying and pasting, note that the first character after 0x is B, not 8.
Close Command Prompt window.
Enjoy running multiple instances of DAZ Studio.

Optional:

Remove sfk.exe from your C:\Windows\System32 folder if you believe you will no longer need it. Or better yet, keep it, because it will allow you to do other awesome things -- for a full list of features and help with examples visit Swiss File Knife website.

That's it, happy ray-tracing!