IDA Pro has included symbol loading facility some time back. But different installations had yield different results; sometimes symbol loading works, sometimes it didn’t. This has led me to scratch my head for an extended period of time until now.
What happened is when IDA ask the following:
IDA Pro has determined that the input file was linked with debug information. Do you want to look for the corresponding PDB file at the local symbol store and the Microsoft Symbol Server?
it made use of its dbghelp.dll and symsrv.dll to load the symbols. We are supposed to accept Microsoft’s terms for using their symbols, but since symsrv.dll is used directly by the plugin the prompt to accept the terms is not displayed, the license cannot be accepted, and hence the symbol loading fails.
The solution is to include an empty symsrv.yes file alongside symsrv.dll in IDA’s directory to indicate that we’d gladly accept the terms that never appear.