The German mutually agreed to cancel his national team contract with the Thai FA and will replace Slavisa Jokanovic at the Thai champions
Schafer has signed a short six-month contract, with the club not revealing any further details.
The German posted details on his Facebook page on Tuesday afternoon to explain the situation that had developed after he had led the War Elephants to the AFF Suzuki Cup final last December.
"Yesterday, the FA of Thailand and me cancelled the contract in mutual agreement,” Schafer updated at 3.30 p.m.
“I am very sad about this development. I had a fantastic time with the kindest and good hearted players. I wish them all the best for the future. I will give you soon more information. Thank you for your support."
He updated his page again 50 minutes later to give the “truth”.
“My team and I came to Thailand hoping to improve Thai football,” Schafer said.
“We worked hard to achieve our goals, but it was a constant struggle, and hope of true development only became dimmer and dimmer.
“After the last half year, after our exciting Suzuki Cup, it became more and more clear that there wasn’t the trust and support given that is needed to work on an international level and the last weeks have confirmed that the future will not bring a change.
“This was and is after all a bad and very, very sad and frustrating situation for the national players, for my team, for me and last but not least for Thailand, for you the fans. So I have decided to cancel my contract.
“The FAT and I found an agreement and now it´s time to move on. I love Thailand. My team and I will miss working with the players, and we wish the national team and all of you all the best.”
Schafer went on to thank the “amazing” Thai supporters for their support, and it was later revealed that he would be staying in the country to coach Muangthong, who announced him as a replacement for Slavisa Jokanovic on Wednesday on their website.