Steps to reproduce:
1. Open the user-supplied project with Unity 5.5.6f1
2. Open the scene SampleScene.
3. Open the file Assets/Localization/Book1.csv in MS Excel
4. Go back to Unity and hit play, notice the file being read in the Console window
5. Move the project to Unity 2019.1 while keeping the file Assets/Localization/Book1.csv opened in Excel.
6. Open the scene SampleScene and hit play.
7. Note the error printed in the console. (It can be expected because the file is being used)
8. Reimport the file with Excel either open or closed.

Expected: The file gets reimported successfully
Actual: The file becomes corrupted: "File couldn't be read"

Reproduced in: 2019.1.0a1, 2019.1.3f1, 2019.2.9f1,
Not reproduced in: 2017.4.33f1, 2018.4.11f1, 2019.3.0a1 (infinite on start), 2019.3.0b6, 2020.1.0a8,

Note: Seems to be fixed in 2019.3 however, I can't find any duplicates and the customer needs the fix for 2019.1 assumingly