Saves created using D2R Loader (https://d2rloader.net/) are not supported -> failed to load file.
Items are stored with some additional data that are normally identified in original D2R (create hero in loader and then it can be used without loader).
Here is the difference in hex for the same starter hero with seven items: 4x hp1, tsc, isc and dgr
Saves created in v3.3.93787, item section only because that is the only difference
Original:
4A 4D 07 00 10 20 A2 00 15 00 00 CF 4F 00 10 20 A2 00 15 04 00 CF 4F 00 10 20 A2 00 15 08 00 CF 4F 00 10 20 A2 00 15 0C 00 CF 4F 00 10 20 A2 00 05 E4 C4 90 08 10 20 A2 00 05 A4 E4 47 22 00 10 20 82 00 0D 11 60 5C 27 94 B4 FB BE 06 04 10 10 AC 59 9C FF 00 4A 4D 00 00 6A 66 6B 66 00 01 00 6C 66 00 00
D2R loader:
4A 4D 07 00 10 00 A2 00 15 00 00 CF 4F D7 19 F9 23 BD 1B 98 02 3E 25 51 51 7F 78 0A 7F 01 10 00 A2 00 15 04 00 CF 4F D5 E3 2C 46 00 AD 92 E6 7A FB 54 22 40 80 23 55 00 10 00 A2 00 15 08 00 CF 4F CB 14 D7 D5 6C 96 92 B6 63 43 C6 9F 48 A0 9A 00 01 10 00 A2 00 15 0C 00 CF 4F 6F 9A AE 84 92 7E 8C 6A 42 C3 1B AC FE 3D 38 D7 01 10 00 A2 00 05 E4 C4 90 68 39 EF B4 95 2C A7 D0 D1 E5 BF 7F E1 F2 49 8B 09 10 00 A2 00 05 A4 E4 47 A2 92 37 0D 06 EC 5F 44 1B 97 A5 50 42 52 80 B4 BE 00 10 00 82 00 0D 11 60 5C 27 84 A3 E9 1D 04 84 1D 23 F6 3A 14 2F 48 8F 8A 33 16 69 E2 6B 97 D8 10 10 AC 59 9C FF 00 4A 4D 00 00 6A 66 6B 66 00 01 00 6C 66 00 00
The difference is in bit no 13 -> InStore.
Then bit no 72 is set (position is not fixed for all items) -> HasRealmData. Realm Data has 4 bytes.
Thus D2R Loader uses online file format