This is due to having less than 520K of free RAM available to run the Field Adjustment Software. If you use a PC running Windows or a network program, you will not have enough memory. Close these programs before proceeding. The majority of the TDS product family products require approximately 520K of free RAM. The two most common places that this error message occurs are the HF and Interleave steps. The PC requests multiple measurements and will save them in the PC Free RAM for later use. When the RAM runs out of space, the PC will continue to add new measurements, overwriting the first measurements that were saved. When the PC attempts to recall them and they have changed, the error message is displayed.