January 22, 2001

Exhibit 10.2.5

January 22, 2001

Paetec Corp.

000 Xxxxxxxxx Xxxxx

Xxxxxxxx, Xxx Xxxx 00000

Re: Lease Amendment/Paetec Building

600 WillowBrook Office Park

Gentlemen:

The purpose of this letter is to amend the Lease Agreement dated July 7, 1999, as amended by letters dated February 11, 2000, March 7, 2000, and December 22, 2000, (the “Lease”) between WillowBrook II L.L.C. (“Landlord”) and Paetec Corp. (“Tenant”) for space at 000 XxxxxxXxxxx Xxxxxx Xxxx, Xxxxxxxx, Xxx Xxxx. I have attached a copy of the facing page of the Lease to this letter.

The Lease is hereby amended as follows:

1. The requirement of Landlord to give Tenant “not less than thirty (30) days prior written notice of the day when Landlord’s Work will be complete and the Demised Premises will be ready for occupancy” is hereby eliminated.

2. Except as modified above, all other terms, provisions and conditions of the Lease shall remain unchanged and are hereby ratified and confirmed.

If the above reflects your understanding, please sign the enclosed copy of this letter and return it to us as soon as possible.

Cordially yours,
WILLOWBROOK II, L.L.C.
By		/s/    XXXXXXX X. XXXXX
		Xxxxxxx X. Xxxxx

The above is hereby accepted and approved,

PAETEC CORP.
By		Xxxxxxx X. Xxxxxxxxxx		EVP				Dated:		2/__/01
		Xxxxxxx X. Xxxxxxxxxx		(Title)