Dforce not working on 4.21?

Is this a new GPU for you? The problem with dForce is not because of the video card, but because of the Nvidia driver for it. Try updating your NVIDIA driver.

Just been reading in the daz forums - it's the game ready drivers from nvidia causing the problem

https://www.daz3d.com/forums/discussion/595931/daz-studio-4-21-0-x-pro-general-release

Getting the same issues here.
I too am using the latest nVidia Game Ready Driver.

You'd think I'd learn not to update Daz right away after all the times it breaks something with an update, but no... I stupidly still update it.

Studio drivers have the same problem... I use them and got the error message too since I updated the driver to the latest version.

anyone tested 526.XX driver? the one that's released today.

apparently the newest 526.98 driver fixes the dforce issue.

Game Ready Driver Fixes (For full list of fixes please check out release notes)

• G-SYNC logo is not displayed in the LG OLED TV menu when connected to GeForce RTX 40 series GPUs [3849595]
• Uncharted: Legacy of Thieves Collection may crash when launched on a GeForce GTX 10 series GPU [3841379]
• [QNIX QX2710/Fujitsu Siemens SL23T-1/Dell UP2715K/ HP Z27q] Unable to select the native resolution of certain monitors from the Windows display settings [3833829][3833632][3689061]
• [Daz Studio] Application crashes after updating to latest driver when trying to run simulation [3838022]
• Desktop Window Manager (dwm.exe) service may report significantly higher GPU usage on certain PC configurations [3830387/3739997]
• Maxon - Cinema4D + Redshift3D vidmemory allocations cause TDR or Driver Crash [3659104]

they also seem to have messed up .tif file types if you have a scene with any .tif textures iray will crash on iray preview and render