There's only one texture used that I'm aware of, the environment texture. I used one from the sIBL archive at http://www.hdrlabs.com/sibl/archive.html and append it here, if it's what you're referring to.

Answering your second question, depends how you mean it. It doesn't crash every time I switch viewport in all cases. But once it crashes on a file, it will crash every time I switch viewport, as long as some changes, as described above, will stop it from happening.

As for your other questions, I haven't tried using CPU, only GPU so far, I will check this out and come back then.

I figured out how to pack all files into the .blend file. So please try the attached file.

Here's the output when starting it from the terminal:

D:\Blender Foundation\Blender>blender.exe
Read prefs: C:\Users\waebbl\AppData\Roaming\Blender Foundation\Blender\2.79\conf
ig\userpref.blend
found bundled python: D:\Blender Foundation\Blender\2.79\python
path not found
path not found
Read blend: D:\Data\Blender\tower\tower_packed.blend
path not found
CUDA error: Unknown error in cuCtxSynchronize(), line 1835

Refer to the Cycles GPU rendering documentation for possible solutions:
https://docs.blender.org/manual/en/dev/render/cycles/gpu_rendering.html


D:\Blender Foundation\Blender>

I tried reducing the tile size all the way down to x:8, y:8 as mentioned in the manual, but it doesn't help. Changing to CPU rendering does not crash blender, so this only happens with GPU rendering.

I just booted up my linux box, downloaded the current stable release and tried the tower_packed.blend file. Here it doesn't crash when I switch viewport, but I haven't updated nvidia-drivers yet, using 378.13 here. Also CUDA is version 8.0.61 toolkit and sdk packages, which is the latest for my distro.
Haven't used linux for some time. I'm running gentoo, there's no relevant output on the terminal.
I'm off until sunday, when I'm back, I'll go and update the nvidia driver and report back on the behaviour.
If you have any questions or suggestions, feel free to ask.
HTH

After updating nvidia-drivers to 384.59-r1, which is the current latest stable release, viewport switching to rendered mode is also working.

@Bernd (waebbl) Did updating the nVidia drivers solve the issue?

@Vuk Sorry I answered by email accidentally.
I didn't notice there's been an update available for windows nvidia driver. I was running it on linux since the report, because it works there. I'll check the new driver and then come back.

Using the 385.69 driver the problem's still there in windows. The output from the console says
CUDA error: Unknown error in cuCtxSynchronize(), line 1835

Refer to the Cycles GPU rendering documentation for possible solutions:
https://docs.blender.org/manual/en/dev/render/cycles/gpu_rendering.html

Is it still an issue with latest builds from builder.blender.org? There was some work related on how CUDA devices are used.

I tried the latest official release from builder.blender.org (#cc96cdd from Oct 24) and also updated to latest nvidia drivers 388.0, but it's still an issue.

If it helps, I can provide a mini dump and related WERReport data, which windows wanted to send home, from the last crash.

Also please note, that I'm completely switched back to using linux and won't use windows actively for the time being, so I don't care a lot about this bug. You're welcome to close it, if the issue is too special or for whatever reason. But if you want to dig further into it, I'm also happy to help you in any way I can and try changes out whenever you say. Just let me know. If I can be of any further assistance, please let me know.

Thanks for your help.