Q: What is the maximum number of files that can part of a profile?
For SyncBackSE and SyncBackFree the maximum number of files depends upon the amount of free memory (RAM) available (and also the amount of memory fragmentation). The following article has details on the memory usage of SyncBackSE:
SyncBackPro, however, is not limited by the amount of free memory. It will use memory (RAM) to store file information until memory runs low or the number of files approaches 200,000. At this point it will move the information from memory to an internal database (stored on the local drive) and use that. This means there is practically no limit to the number of files that can be processed (the limit then becomes the amount of free disk space).