The answer is
A PDB file contains information used by the debugger. It is not required to run your application and it does not need to be included in your released version.
You can disable pdb files from being created in Visual Studio. If you are building from the command line or a script then omit the /Debug switch.
I had originally asked myself the question "Do I need a PDB file deployed to my customer's machine?", and after reading this post, decided to exclude the file.
Everything worked fine, until today, when I was trying to figure out why a message box containing an Exception.StackTrace was missing the file and line number information - necessary for troubleshooting the exception. I re-read this post and found the key nugget of information: that although the PDB is not necessary for the app to run, it is necessary for the file and line numbers to be present in the StackTrace string. I included the PDB file in the executable folder and now all is fine.
PDB is an abbreviation for Program Data Base. As the name suggests, it is a repository (persistent storage such as databases) to maintain information required to run your program in debug mode. It contains many important relevant information required while you debug your code (in Visual Studio), for e.g. at what points you have inserted break points where you expect the debugger to break in Visual Studio.
This is the reason why many times Visual Studio fails to hit the break points if you remove the *.pdb files from your debug folders. Visual Studio debugger is also able to tell you the precise line number of code file at which an exception occurred in a stack trace with the help of *.pdb files. So effectively pdb files are really a boon to developers while debugging a program.
Generally it is not recommended to exclude the generation of *.pdb files. From production release stand-point what you should be doing is create the pdb files but don't ship them to customer site in product installer. Preserve all the generated PDB files on to a symbol server from where it can be used/referenced in future if required. Specially for cases when you debug issues like process crash. When you start analysing the crash dump files and if your original *.pdb files created during the build process are not preserved then Visual Studio will not be able to make out the exact line of code which is causing crash.
If you still want to disable generation of *.pdb files altogether for any release then go to properties of the project -> Build Tab -> Click on Advanced button -> Choose none from "Debug Info" drop-down box -> press OK as shown in the snapshot below.
Note: This setting will have to be done separately for "Debug" and "Release" build configurations.
Program Debug Database file (pdb) is a file format by Microsoft for storing debugging information.
When you build a project using Visual Studio or command prompt the compiler creates these symbol files.
Check Microsoft Docs
Source: Stackoverflow.com