Steps to repro:

1. Open attached project and 'TestScene';
2. Go to Lighting settings window (Window>Lighting>Settings);
3. Click 'Generate Lighting' button;
4. Wait until 'Baking... ETA' stage begins;
5. In the 'Mixed Lighting' section unselect 'Baked Global Illumination' checkbox;
6. Observe the Console.

Actual result:
Errors

- Failed copying the texture from 'C:/Users/vlka/AppData/LocalLow/Unity/Caches/GiCache/b5/b577ce4c088736883933d0a508e65bff._comp_light.exr' to 'Temp/GI/aed21595ca498bb2e237af1725ce65cb/Lightmap--1_comp_light.exr'

- Failed to copy lightmap snapshot assets to directory: Temp/GI/aed21595ca498bb2e237af1725ce65cb

and

-Assertion failed on expression: 'm_PendingLightmapHashes.size() == m_LightmapCompositeHashes.size()'

are shown. See attached video.

Regression introduced in Unity 2018.1.0a1.

Expected result:
No errors are shown after unselecting Baked GI checkbox.

Notes:
- Reproducible in 2018.2.0a1, 2018.1.0b2, 2018.1.0a1;
- Not reproducible in 2017.3.0p1, 2017.2.1p2;
- Reproducible only for PLM; not reproducible for Enlighten.