So I just bought a Pro Mini the other day, however, I didn't get an FTDI cable or a USB/Serial converter board. From what I understand from this article I can use my Arduino Uno 101 to push sketches onto the Pro Mini.
The wires are all hooked up (grounded reset on the Uno) and I have uploaded the sketch to disable the serial communication port on the Uno, however, when I try to push a sketch to the Mini it errors out with the following message
Arduino: 1.8.3 (Windows Store 22.214.171.124) (Windows 10), Board: "Arduino Pro or Pro Mini, ATmega328 (5V, 16 MHz)" Sketch uses 928 bytes (3%) of program storage space. Maximum is 30720 bytes. Global variables use 9 bytes (0%) of dynamic memory, leaving 2039 bytes for local variables. Maximum is 2048 bytes. avrdude: ser_open(): can't open device "\\.\COM3": The system cannot find the file specified. Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions. This report would have more information with "Show verbose output during compilation" option enabled in File -> Preferences.
The only part of the suggested troubleshooting guide that maybe applicable is the drivers section.
The Arduino Uno and Mega 2560 use standard drivers (USB CDC) provided by the operating system to communicate with the ATmega8U2 on the board. Other Arduino boards use FTDI drivers to communicate with the FTDI chip on the board (or in the USB-serial convertor).
I could be wrong but to me it doesn't seem like the second sentence applies to this situation since the the Uno sits between the pc and the mini. However, when I check the windows device manager I can see that the Uno is connected on a COM port, but nothing about the Mini. Though I am not sure that it should show up.
I am using the IDE(1.8.3) to program and "Arduino Pro or Pro Mini" as the board. Though Tools>Port is greyed out when I have this board selected.