Always use a CAST AIP setup installation. For reproducing issues, flat installation is not recommended because the analysis/snapshot may fail. This can be due to files that are missing in the flat installation.
Map the source code path in order to respect the deployment defined in configuration.
Go to the Current Version tab and check the path of AU whether it is mapped to the same path of the deployment folder.
If customer provides the complete source code then the complete source code should be in the mapped deploy folder.
If customer provides only couple of files as requested by support, then recreate the user defined analysis unit and add the files in the specific configuration tabs to analyze those files. Refer page
Running the analysis depends on the type of issues as below: Crash/Fatal error: If the analysis unit causing the crash is not known then run the full analysis if it is known run only that particular analysis unit by annotating it. Beware sometimes the reproduction of Crash is not reproducible when we run only couple of analysis unit due to dependency so in that case study the dependent analysis unit and then run those analysis units in one execution unit. Syntax error warnings: It is not advisable to run the complete analysis while reproducing the syntax error only running couple of files giving syntax error or particular analysis unit is enough, this will save time. Other warnings: If the warning is related to unresolved objects, you should check if the relevant source code is present in the deploy folder. Also never annotate the analysis unit rather study the case and check the dependency and annotate the analysis unit accordingly to reproduce quickly. Performance issue: Check in the analysis log and see which analysis unit is taking more than expected time and try to run only that analysis unit and see if the issue is getting reproduced. If the analysis log does not give clarity on analysis unit (performance issue while loading the configuration, saving phase) then run the analysis on whole source code.
Configure DLM only if the issue is related to DLM. If not required delete it from CAST-MS because while configuring the analysis you might not have the dlm.xml file, for more info refer thispage
Only if the issue is related to missing links and reference pattern, configure reference pattern otherwise remove it from CAST-MS, for more info refer thispage
If you don't require the settings in"Tools before analysis" and "Tools after analysis" for your reproduction then remove these configurations from Content Enrichment tab in CAST-MS, for more info, refer this page
Uncheck the analysis units of other technologies if you have other technologies apart from the technology that is being analyzed but in case of missing links between inter technologies (for ex: missing links between ABAP method and DB table) you have to be careful while unchecking the analysis units of other technologies. This will shorten down the analysis run time, for more info, refer this page
If Architecture model is configured, the same configuration should be made, for more info, refer this page
Check all the tabs in the CAST-MS for different configuration done by customer, make sure you have the same configuration otherwise your analysis will fail at some other step and you will end up with different issue.