UNITED STATES
                     SECURITIES AND EXCHANGE COMMISSION
                           Washington, D.C. 20549


                                SCHEDULE 13D

                 Under the Securities Exchange Act of 1934
                             (Amendment No. 6)*


                            ARCH WIRELESS, INC.
                  (f/k/a Arch Communications Group, Inc.)
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                              (Name of Issuer)

                   Common Stock, par value $.01 per share
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                       (Title of Class of Securities)

                                 039392105
                             -----------------
                               (CUSIP Number)

                            Jessica Forbes, Esq.
                  Fried, Frank, Harris, Shriver & Jacobson
                             One New York Plaza
                          New York, New York 10004
                               (212) 859-8558
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    (Name, Address and Telephone Number of Person Authorized to Receive
                        Notices and Communications)

                                May 23, 2001
                       ------------------------------
          (Date of Event which Requires Filing of this Statement)


If the filing  person has  previously  filed a statement on Schedule 13G to
report the  acquisition  that is the subject of this  Schedule  13D, and is
filing  this  schedule  because  of ss.ss.  240.13d-1(e),  240.13d-1(f)  or
240.13d-1(g), check the following box |_|.

NOTE:  Schedules filed in paper format should include a signed original and
five copies of the schedule,  including all exhibits.  See ss. 240.13d-7(b)
for other parties to whom copies are to be sent.

*The  remainder  of this cover  page  shall be filled  out for a  reporting
person's  initial  filing on this form with respect to the subject class of
securities,  and for any subsequent amendment containing  information which
would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities  Exchange Act
of 1934 ("Act") or otherwise  subject to the liabilities of that section of
the Act but shall be subject to all other  provisions  of the Act (however,
see the Notes).

CUSIP No. 039392105                  13D

1   NAMES OF REPORTING PERSONS
    I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only)

           Whippoorwill Associates, Inc.
           13-3595884

2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP     (a)  [ ]
    (See Instructions)                                   (b)  [ ]

3   SEC USE ONLY

4   SOURCE OF FUNDS (See Instructions)

     OO; WC

5   CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
    PURSUANT TO ITEMS 2(d) or 2(e)                           [ ]

6   CITIZENSHIP OR PLACE OF ORGANIZATION

     Delaware

  NUMBER OF      7  SOLE VOTING POWER

   SHARES

 BENEFICIALLY    8  SHARED VOTING POWER

OWNED BY EACH       8,826,439

 REPORTING       9  SOLE DISPOSITIVE POWER

PERSON WITH

                10  SHARED DISPOSITIVE POWER

                    8,826,439

11  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

          8,826,439

12  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11)             [ ]
    EXCLUDES CERTAIN SHARES (See Instructions)

13  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

          4.9%

14  TYPE OF REPORTING PERSON (See Instructions)

          IA, CO


                                SCHEDULE 13D
                                ------------



ITEM 1.     SECURITY AND ISSUER.


            This Statement on Schedule 13D (this "Statement") relates to
the Common Stock, par value $.01 per share (the "Common Stock"), of Arch
Wireless, Inc. (formerly known as Arch Communications Group, Inc.), a
Delaware corporation (the "Issuer"). The principal executive offices of the
Issuer are located at 1800 West Park Drive, Suite 250, Westborough, MA
01581. The Statement amends the Schedule 13D filed by Whippoorwill
Associates, Inc. ("Whippoorwill") on June 14, 1999 as amended through
February 21, 2001.

ITEM 2.     IDENTITY AND BACKGROUND.

            No change.

ITEM 3.     SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION.

            No change.

ITEM 4.     PURPOSE OF TRANSACTION.

            No change.

ITEM 5.     INTEREST IN SECURITIES OF THE ISSUER.

            Item 5 is amended in its entirety as follows:

            (a) The percentages set forth in this Item 5 are based on the
Form 10-Q filed by the Issuer on May 23, 2001, which stated that as of
April 18, 2001 there were 181,753,093 shares of Common Stock outstanding.

            The Holders, in the aggregate, directly own 8,386,535 shares of
Common Stock representing approximately 4.6% of the outstanding Common
Stock. The Holders, in the aggregate, own 1,319,713 Participation Warrants,
which are exercisable into 439,904 additional shares of Common Stock.
Therefore, the Holders, in the aggregate, beneficially own 8,826,439 shares
of Common Stock, representing approximately 4.9% (computed in accordance
with Rule 13d-3(d) under the Act) of the outstanding Common Stock.

            (b) Although Whippoorwill does not own any of the Common Stock,
since Whippoorwill has discretionary authority with respect to the
investments of and acts as agents for its clients, Whippoorwill has shared
power to vote the 8,826,439 shares of the Common Stock beneficially owned
by the Holders. The information required by Item 2 with respect to
Whippoorwill is set forth in item 2 above.

            (c) Not applicable.

            (d) Not applicable.

            (e) Whippoorwill ceased to be the beneficial owner of more than
5 percent of the Common Stock due to a public filing by the Issuer on May
23, 2001.


ITEM 6.     CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS
            WITH RESPECT TO SECURITIES OF THE ISSUER.

            No change.


ITEM 7.     MATERIAL TO BE FILED AS EXHIBITS.

            No change.



                                 SIGNATURES
                                 ----------

            After reasonable inquiry and to the best of its knowledge and
belief, the undersigned certifies that the information set forth in this
statement is true, complete and correct.

Dated:  August 7, 2001



                                WHIPPOORWILL ASSOCIATES, INC.


                                By:  /s/ Shelley F. Greenhaus
                                     --------------------------------------
                                     Name:   Shelley F. Greenhaus
                                     Title:  Managing Director