There still are mobile workstation laptops with ECC memory, e.g. the Dell Precision 5000/7000 series and some similar series at HP and Lenovo. My own laptop is

There still are mobile workstation laptops with ECC memory, e.g. the Dell Precision 5000/7000 series and some similar series at HP and Lenovo. My own laptop is such a Dell Precision model. EDIT: Looking now at the Dell site, I see that buying a laptop with ECC memory has become much more difficult than a few years ago. For many of the "mobile workstations" ECC memory is not offered at this time, while for those where you can customize the laptop and choose ECC, the price is absolutely outrageous, e.g. $850 for 64 GB of ECC memory. Of course, anyone sensible would buy the "mobile workstation" with the smallest and cheapest memory option, then they would buy separately 64 GB of ECC SODIMM memory at a price 4 times lower than demanded by Dell.