Manchester United have written to Everton to apologise over the manner in which they went about hiring David Moyes, reports the Daily Mirror.
The Merseysiders are still livid at the the Premier League champions after it was revealed by Moyes himself that United approached him months before the official announcement was made.
Manchester United chiefs have now tried to diffuse the row in an attempt to convince the Toffees not to launch an official complaint to the Premier League.
The Old Trafford outfit are also worried that the feud will end any hope of United signing Everton left-back Leighton Baines.
An increase on their rejected £12million bid was expected to be launched in the coming weeks but it is thought that relations must be patched-up before a deal can move forward.
Not only were Everton annoyed with the early approach for Moyes, but are furious that the public announcement was made over three weeks before the end of the season, without the club's permission.
It is now believed that only a huge offer will tempt Everton officials to accept a bid from Manchester United for Baines.
The fallout will not hamper Moyes' attempts to sign Marouane Fellaini should he decide to up his interest in the Belgian, however.
Fellaini has a release clause of £23million that Everton would have no choice but to accept should an offer come in.
If Moyes fails in his attempts to sign Cesc Fabregas it is believed he will meet the powerful midfielder's clause.