There are 2 file types use the .MYD file extension:
1. MySQL Database Data File
Database file created with MySQL, a popular open source database management system; contains the actual data stored within the rows of the database.
MYD files are saved with a corresponding .FRM file that contains the table format data, and an .MYI file, which serves as the database index.
Updated: August 18, 2018
2. Everfine Photomoetric Results File
An MYD file is an encoded text file created by Everfine photoelectrical instruments, which are used to measure the performance of and calibrate LED lights. It contains LED lighting photometric report results, such as the test time, lumen flux, and any remarks about the test. MYD files are typically generated from individual LED tests.
You most likely will only come across this type of file if you use Everfine measuring instruments and are an LED lighting professional. If you need to open an MYD file, you can use Everfine LEDSpec.
Updated: November 7, 2017