After seven stages, the Finn is ahead of Briton Elfyn Evans, also in a Toyota, by 22.4 seconds and Estonian Ott Tänak (Hyundai) by 25.3 seconds.
Loeb had to retire after the 4th special, a fire having broken out in his engine.
"It's frustrating to retire like this because the feelings were good, the car was good and we had prepared well (...). The rally is very hard, a lot of dust and stones. It's disappointing but we we can't do anything about it," said the nine-time French world champion who was in 5th place before his retirement.
Its previous and only participation so far in the Kenyan rally dates back to 2002. This event was then removed from the WRC world championship calendar before returning to it last year, the victory then going to Sébastien Ogier, him -even eight-time world champion.
The 4th and 7th specials (the same route contested in both directions) proved to be particularly difficult due to the ruts of sand and dust mixed with stones.
Ogier was the victim with a puncture which made him lose the lead of the race and demoted him to more than two minutes from the leader.
Sébastien Loeb's M-Sport Ford was forced to retire after the 4th special of the Kenya Rally in Naivasha, June 24, 2022 Tony KARUMBA AFP
"It's going to be difficult to fight for the lead now but anything can still happen," said Ogier who, like Loeb, now only makes selected appearances in the world championship.
Thierry Neuville (Hyundai) also suffered from the racing conditions.
The Belgian had to slow down on the 4th special, with a clogged air filter, and finds himself 5th in the provisional classification, almost a minute behind Rovanperä.
Two other Ford drivers, Briton Gus Greensmith and Irishman Craig Breen suffered breakdowns while Frenchman Adrien Fourmaux was tied down by transmission problems, marking a real black Friday for the M-Ford team.
The rally continues on Saturday with 6 specials and will end on Sunday.
Classification of the Kenya Safari Rally, sixth round of the World Rally Championship (WRC), Friday after the 7th special (SS7):
1. Kalle Rovanperä - Jonne Halttunen (FIN / Toyota) 1h20:58.1
2. Elfyn Evans - Scott Martin (GBR/Toyota) +22.4
Sébastien Ogier at the wheel of his Toyota during the 4th special of the Kenya rally around Naivasha, June 24, 2022 Tony KARUMBA AFP
3. Ott Tänak - Martin Järveoja (EST / Hyundai) +25.3
4. Takamoto Katsuta - Aaron Johnston (JPN-IRL/Toyota) +26.6
5. Thierry Neuville - Martijn Wydaeghe (BEL/Hyundai) +57.5
6. Sebastien Ogier - Benjamin Veillas (FRA / Toyota) +2:08.2
7. Oliver Solberg - Elliot Edmondson (SWE-GBR/Hyundai) +4:27.1
8. Kajetan Kajetanowicz - Maciej Szczepaniak (POL/Skoda) +9:51.1 1st WRC2
9. Craig Breen - Paul Nagle (IRL/M-Sport Ford) +10:24.6
10. Sean Johnston - Alex Kihurani (USA/Citroen WRC2) +11:04.6
11. Jourdan Serderidis - Frédéric Miclotte (GRE-BEL/Ford)
12. Gus Greensmith - Jonas Andersson (GBR-SWE/M-Sport Ford) +14:38.2
13. Adrien Fourmaux - Alexandre Coria (FRA / M-Sport Ford) +7.1
Special stage winners: Ogier (SS1, SS5, SS7);
Rovanpera (SS3, SS4, SS7), Loeb (SS1)
Main DNFs: Sebastien Loeb (Ford)
.jld/hpa
© 2022 AFP