To reproduce:

1. Download and open attached "repro980524.zip" project.
2. Open "scene" Scene.
3. Open "TestProfiler.cs" script and set correct path to your profiler file to be saved.
4. Enter Play mode.
5. Notice the console. Soon after start, Log should appear saying that Profiling has started.
6. Wait till Profiling stops. Log should appear in the console saying that it stopped.
7. Locate "abc.data" file which was created by profiler in your specified directory in step 2.
8. Try to open it without closing unity editor.

Expected result: File is opened with selected application/code editor or it can be loaded in the unity profiler without closing or reopening the editor.
Actual result: File fails to open. Error is thrown that file is opened by another application.

Workaround: Close or reopen Unity editor. Now file can be opened with a selected text/code editor.

Reproduced with: 2018.1.0b1, 2017.3.0p1, 2017.2.1p1, 2017.1.3f1, 5.6.5f1.

Notes: Notice that before closing the editor, abc.data file size is 0. After trying to open it, file size is updated but it still cannot be viewed with any application. For opening the file Notepad++ and "VS code" text/code editors were used. Same issue happened when running the project with standalone player built. Created file cannot be opened while a game is running.