A biometric F-Series hand reader usually comes with standard user memory.  When a user is added that exceeds that user memory size, there is no room left to store that user and that user template cannot be added to the reader database.  The reader appears to not have worked.  When this happens, check the memory size on the hand reader.

To determine what memory size is on a F-Series HandKey or a F-Series HandPunch, press the * (asterisk) key 15 times.  For a HandKey II or a HP 3000, the top panel will display:  128K for standard memory; 256K for 9,728 users (EM-801/801-F3); and 640K for 32,512 users (EM-803/803-F3). On a HP 4000, the top panel will display:  530 users for standard memory and 3,498 users (EM-805/805-F3).  On a HP 1000, the top panel will display:  50 users for standard memory, 100 users (EM-701), and 512 users (EM-702 or EM-703).