You can back-up your projects using the Export Synergy Project function. This function insures that template and generated code isn't stored- this code will get regenerated so it need not be archived. Additionally, uncheck the debug folder from archiving since it can be very large, but can also be regenerated. For most projects you only need are the configuration.xml file, the xxx.pincfg file and the hal/thread_entry files in /src. Export Synergy Project does just that.
If you change the project settings and custom linker flags and pre-processor defines they won't carry over if only the files mentioned previously are used, so we recommend only very experienced uses deviate from using the Export function
You can easily import your archived projects using the Import Projects into Workspace, or the Rename and Import Existing C/C++ Project into workspace if you need to change the project name.