After having fixed a number of events that lost its files this window pops up when trying to build. I tried by root-cause-analysis to delete the events and build and continued that process until Fmod was able to build. And it turned out that it was all the events that some if I deleted about 70 percent of all events I could build. Is there any way this can be fixed ? Any help would be appreciated !
This error message indicates that your operating system prevented FMOD Studio from either writing a bank file or reading a source file. Since you’re able to build the bank after deleting certain events, it is likely that your source files are the problem.
We recommend enabling verbose logging in the console window. This will cause the operating system error message(s) associated with the problem to appear in the console window’s “Logging” tab.
Some forms of source control (including folders synchronized to online file storage utilities such as DropBox) are known to regularly open and close files for reading and writing, which can blocks FMOD Studio from opening those files for reading or writing. To avoid this issue, we recommend using an FMOD Studio source control integration instead of a source control solution that’s entirely external to FMOD Studio.
Hi thanks for the reply.
The red arrow points to the event that causes the project not to build.
But I cant see any information in the Log that relates this event to the error.
How come the Log doesnt tell that this particular event causes the error ?
Thomas 
Without knowing the nature of the error, I can’t yet discern why it isn’t appearing.
Looking at your logs, I see a lot of Lookup failed for ParameterLayoutModel messages. These usually indicate that a parameter sheet is missing or could not be found. This might be due to a merging error, due to a file not being found, or due to file corruption. Did you try removing your project from source control and Dropbox, as I suggested in my previous post?
I notice the instrument you’ve marked with a red arrow in your screenshot is blank, as if it has no associated event or content. Can you confirm whether this is the case? And do you know what that instrument is supposed to do? Your describing it as an event makes me think it must be an event instrument; if so, does the associated event still exist?
Hi again Joseph.
First of all I should remember saying that we already found out what the problem was in the project. Its an instrument that is missing its reference and yes - the instrument is empty (ref the red arrow). So when I remove that instrument Then I can build again.
So I did solve the problem, but I have 2 things I am wondering about.
- Is there a way I can get the instrument with missing reference to find its audio file again.
In Cubase there is a function called - ‘find missing audiofiles’
2.My developer also had a look at the Log and he was wondering why there was nowhere it was telling us that this empty instrument was the problem.
Hope this makes my question more clear.
If you look in the assets browser, all missing audio files are highlighted as missing. If you type “#missing” into the assets browser search bar, it will display only missing assets and their containing folders.
You can replace any of these audio files with another imported audio file by right-clicking on the file and selecting “Replace with” from the context menu.
Without having access to your project to determine the nature of the problem, there is no easy way for us to determine why it does not show up in the logs.
Usually, when an audio file goes missing, it does not cause a project to fail to build; instead, it results in the instruments that reference that file not producing audio, and the project otherwise functioning as it should. Also, the instrument in your screenshot is missing a label as well as its content, something that should be impossible to achieve through the UI. These two details make me suspect that the file containing that instrument was somehow corrupted.
Unfortunately, there is no easy way to identify how that occurred. It may have been corrupted by a bad merge, an incomplete script, the Studio process being terminated unexpectedly, or by a drive error. There may be some clue in your project itself, but again, without access to your project, our ability to investigate is limited.
Ok interesting I will try that out if it happens again.
Yes its difficult to investigate. I think I will just leave it here as I already found the solution as described above. Lets just hope it doesn not happen again. Thanks for your time 
Thomas