Please take a close look at RealFlow | Cinema 4D's list of limitations and known bugs. It is a valuable resource when you encounter problems, crashes, or difficulties:
Cinema 4D R15, R16, R17, R18, R19, R20, R21, R22 and R23 (64 bit only)
Windows 7 (or higher) or macOS 10.9 (or higher) operating system.
CPU 64-bit Intel® or AMD® multi-core processor.
8 GB RAM.
100 MB disk space for installation.
Network adapter and internet access for license activation.
RealFlow | Cinema 4D supports GPU-based simulations and multi-core/multi-processor systems.
Since fluid simulations are computationally expensive and allocate large amounts of disk space we recommend Intel® i7 or Xeon systems (or comparable), 16 GB RAM (or more) and a 512 GB hard disk drive/SDD.
RFCFD-692 - Cinema 4D R23 support.
RFCFD-351 - Array Tool: Parameters can't be animated for meshes.
RFCFD-517 - Initial State files created in RealFlow | Cinema 4D 1.0 are not compatible with 2.0 version due to the switch from RPC to Alembic.
RFCFD-580 - Mesh fluid/emitter weight vertex map computation is limited to a maximum amount of 10.
RFCFD-358 - File paths can't have unicode characters on macOS.
RFCFD-519 - Simulation steps configuration from RealFlow | Cinema 4D 1.0 scenes is reset to Auto mode when opened in version 2.0 and higher.
RFCFD-469 - Simulation look on render may differ between multiple simulation/renders unless caching is enabled.
RFCFD-486 - Objects deformed with Rigid, Elastic and Particle Skinner only support motion blur when using the Point Cache tag.
RFCFD-499 - Particle render instances are not rendered/recognized by NVIDIA's Iray.
RFCFD-500 - Motion blur with meshes doesn't work with NVIDIA's Iray.
RFCFD-501 - Motion blur with meshes doesn't work with Maxwell Render.
RFCFD-522 - Emitter ID value is not preserved on scene reopening.
RFCFD-551 - Having two or more k Isolated daemons linked to the same fluid makes the isolation value grow as many times as the number of k Isolated linked daemons.