
Microsoft Excel Patch for
  the "15 digit number" bug
  the "Link to same cell different sheets" bug
  the "Transposing ranges" bug
  the "Single cell dependency" bug
Microsoft Excel 7.0 (95) Version

Thank you for using Microsoft Excel.  Along with this readme you should
have received a file called PATCHXL.EXE.  This patch will fix four bugs:
the "15 digit number" error in Microsoft Excel that was discovered in
September 1995, the "link to the same cell in a different sheet" bug,
the "transposing ranges" bug, and the single cell dependency bug discovered
in December 1995.  The "More Information" section of this
readme contains a full description of the problems.

To install the patch, copy the PATCHXL.EXE into the same directory where you
installed Excel 7.0.  Double-click on the patch from File Manager in Win/NT 3.51
or the Windows Explorer in Win 95.  A Command Prompt window will appear briefly
and then disappear.


To verify that patch #1 is installed correctly, boot Excel and enter 
1.40737488355328.  If the number maintains the correct value upon entry,
the patch has been successfully installed.

NOTE:  You will receive an error message if the first patch has already
been installed saying that the first patch was not applied.  This is expected,
and the above verification will tell you if your EXE indeed is fixed.


To verify patch #2 and #3, enter the number 5 into cell K25 on Sheet1.  Select Sheet2,
, type "=", and click once in cell K25 on Sheet1. Press enter, and the two cells
will be linked.  Select Sheet1 again, and change the number in cell K25.
Select Sheet2; if the number hasn't changed, the patch isn't applied.  If
it has, then the patch has correctly been installed.


To verify path #4, enter the number 1 in cell A1 on Sheet1.  Select cell A3 and enter
the formula "=A1".  Then select cell B2 and enter the formula "=A1" (the formulas
must be entered in this exact order).  Now change the number in cell A1 to 2.  If the
numbers in cells A3 and B2 do not both update to the value then the patch has not
been installed.  If the numbers in cells A3 and B2 both update to 2 then the
patch has correctly been installed.


Thank you again for using Microsoft Excel.  We hope these problems have not
inconvenienced you.  If you have any further questions, please call Product
Support.


MORE INFORMATION - 15 digit bug
===============================

In Microsoft Excel for Windows 95/Windows NT, certain 15 digit
numbers may unexpectedly change value when they are entered into a
worksheet cell or when they are calculated by a formula in a worksheet
cell. The three numbers are:

   140737488355328
   281474976710656
   562949953421312

If you enter a variation of these numbers (for example,
1.40737488355328), or if you calculate a variation of one of these
numbers, the number may resolve to a different value, such as 0.64 (or
some multiple of 0.64).

The following information is taken from a Questions and Answers file
that was posted on the CompuServe Information Service. This information
was originally posted on September 22, 1995.

1.  Q. I heard there is a problem with Excel changing the values of some
       specific numbers, whats the situation?

    A. In Microsoft Excel there is an error that will cause three
       specific sequences of fifteen digits to change their value either
       when entered as an individual entry or when derived from specific
       functions. This was brought to our attention earlier this week
       and we are in the process of creating a solution that will be
       available within the next 10 days to correct the situation.

2.  Q. Can you tell me what that means in more common terminology?

    A. What this means is that if you have entered one of three specific
       fifteen digit numbers or come to this number as the result of a
       formula, Microsoft Excel might have changed the value of the
       number.

3.  Q. What are the chances that I have been affected?

    A. Although it is hard to have an exact number, we believe this will
       only affect a very small number of customers. In fact, based on
       our internal analysis the likelihood of any one of these sequence
       of digits appearing in a customers spreadsheet is approximately
       1 in 5 billion. Remember, the only way that this will affect you
       is if you have these three specific combinations of fifteen
       digits.

4.  Q. If there is such a small likelihood of this occurring, why worry
       about fixing it?

    A. Our customers depend on Microsoft Excel to compute their numbers
       accurately and we want them to feel confident when using the
       product. Even though the probability of  one of our customers
       having a problem with this is low, we cant judge the probability
       for each and every customer. So, we are trying to get all of the
       facts regarding this out so that you can determine for yourself
       if you need the patch. The solution will be available to all
       customers that own Microsoft Excel or Microsoft Office. This
       patch will be available at no charge beginning October 1, 1995 in
       the U.S.

5.  Q. What are you doing to fix this?

    A. We have created a solution that will correct this error. We are
       in the process of testing this solution on various hardware, it
       will be available in the form of a patch which we will make
       available beginning on October 1, 1995 in the U.S.

6.  Q. So, what are the numbers that cause this error?

    A. The specific sequences of digits are: 140737488355328,
       281474976710656 and 562949953421312. The decimal point may be in
       different places. In addition if you are dealing with
       calculations, the result has to be one of these three sequences
       of digits, plus or minus a number less than approximately one-
       half of the next decimal, times a power of 10. And this is only a
       problem when you refer to the result in certain functions,
       namely: int(), ceil(), floor(), roundup(), and if().

7.  Q. Why these specific numbers?

    A. The common bond between these numbers is that they happen to be 2
       to the 47th, 48th, and 49th power, respectively.

8.  Q. Does this mean I have to check to make sure any 15 digit numbers
       in my files have not been changed by Excel?

    A. No. Unless you entered in one of the three specific sequence of
       digits mentioned above or have utilized one of the specific
       formulas mentioned above with very long numbers you should be
       fine. To double check, however, all you have to do once you have
       installed the patch is to open a file and press Control/Alt/F9,
       by doing this the patch will correct any numbers that were
       derived from functions incorrectly.

9.  Q. How did you find out about this?

    A. One of our customers actually found it when they were working
       with a formula that derived the number 1.40737488355328. This
       customer's work required that he create a formula in Microsoft
       Excel which explicitly calculated 2 to the 47th and take the
       integer portion of it. We were not previously aware of this error
       and are grateful that it was brought to our attention.

10. Q. What versions of Microsoft Excel does this affect?

    A. We have found this in versions of the product dating back to
       Excel 3.0 for Windows, the Macintosh and OS/2. Other versions of
       the product affected include Microsoft Excel 4.0 for Windows and
       the Macintosh, Microsoft Excel 5.0 for Windows, Windows NT and
       the Macintosh, and Microsoft Excel for Windows 95. We will make
       the patch available for no charge for any of our customers using
       any of these versions of Excel.

11. Q. How do I get the patch?

    A. Simply call Microsoft at (206) 635-7070 on or after October 1,
       1995 and the patch will be sent to you at no charge. Our goal is
       to have the patch available for the Windows 3.1 and Windows 95
       versions of the product beginning on October 1, 1995 with other
       platform versions following soon thereafter.


MORE INFORMATION - Link to same cell bug
========================================

In Microsoft Excel for Windows 95 there is an error that will occur when you
have linked certain specific cells from one sheet in a workbook to the same
exact cells in another sheet in the same workbook.  Basically, what happens
is that if you change your data after those specific cells have been linked,
the data will not update on the second sheet.  This was brought to our attention
by a customer and we have created a solution that fixes the problem.

Our customers depend on Microsoft Excel to compute their numbers accurately
and we want them to feel confident when using the product.  If there is a
problem we take it seriously and we provide as much information as possible
so that customers can decide for themselves if they need the patch.   

Remember, this will only occur when linking a specific cell on a sheet in a
workbook (for example, cell S20) to that same cell on another sheet in the
same workbook.  The most common way for this to occur would probably be
if a customer created a "roll up sheet" that speared data from one cell
in a sheet to the same exact cell in an another sheet in the same workbook. 

This only affects Microsoft Excel 7.0.  Once the patch is applied, any sheets affected
by this problem will automatically work correctly (ie there's no conversion
required to correct the problem in the sheets).

MORE INFORMATION - Transposing Ranges bug
=========================================

In Microsoft Excel for Windows 95 there is a problem that will cause Excel to
become unstable if you transpose a range that contains a reference.  Transposing
a range means that you copy a range and then use the "transpose" option in the Paste
Special dialog, which reverses the rows and columns (ie the row-wise cells are
turned column-wise and vice-versa).  Once the patch has been applied, this
action should complete normally.

MORE INFORMATION - Single Cell Dependency bug
=============================================

In Microsoft Excel for Windows 95 there is an error that can occur when you have
two or more cells that are dependent through a formula to another specific cell.
What can happen is that if a number in a given cell is changed, it is possible the
recalculation may not occur in other cells that are dependent on this cell.  For this
to occur, there must be formulas connecting two or more cells to the specific cell
where the number has changed and these formulas need to have been entered in a
particular order.  This was brought to our attention by a customer and we have
created a solution that fixes the problem for Microsoft Excel users.

The following information is taken from a Questions and Answers file
that was posted on the CompuServe Information Service. This information
was originally posted on December 12, 1995.

1.  Q. I heard there is an error that occurs with recalculation when two or more cells
       are dependent upon a single cell in Microsoft Excel, whats the situation?

    A. In Microsoft Excel for Windows 95, an error can occur when you have two or
       more cells that are dependent (through a formula) on another specific cell.
       If a number in a given cell is changed, it is possible the recalculation may
       not appear in other cells that are dependent on this cell.  For this to occur,
       there must be formulas connecting two or more cells to the specific cell where
       the number has changed and these formulas need to have been entered in a
       particular order (from the bottom up - entering references to a cell above
       previous references to the same cell).  In addition, the dependent and precedent
       cells must be in different columns. This was brought to our attention by a
       customer and we have created a solution that fixes the problem for Microsoft
       Excel users. 

2.  Q. What are the chances that I have been affected?

    A. Although scenarios where multiple cells are dependent upon a single cell are
       common, we feel relatively few people have been affected since it occurs only
       when the formulas have been entered in a specific order, when the formulas
       connect two or more cells to a single cell where the number has changed, and
       when the dependent cell is in a different column than the precedent.  You can
       very easily ensure accuracy in your spreadsheet simply by pressing Ctrl Alt F9
       (the recalc keyboard command).  This will force Microsoft Excel to update all
       of your cells.  In addition, once a user closes and reopens a workbook containing
       the error, the link is restored.  Also, we have received no support calls on this
       issue other than the customer who brought it to our attention.  Regardless, we
       feel it is important to offer customers a solution as quickly as possible.

3.  Q. If this wont affect that many people, why bother fixing it?

    A. Our customers depend on Microsoft Excel to compute their numbers accurately and we
       want them to feel confident when using the product.  If there is a problem we take
       it seriously and we provide as much information as possible so that customers can
       decide for themselves if they need the patch.   

4.  Q. What are you doing to fix this?

    A. We have already created and posted a solution that will correct this error.  The
       solution or "patch" will be available on line beginning the week of December 11 in
       the U.S.

5.  Q. Have you notified customers?

    A. Yes, we have alerted accounts we regularly work with.  In addition, we have posted
       this on-line for end users. 

6.  Q. Is there a workaround I can use if I dont want to wait to get the patch?  

    A. Yes.  The most direct workaround is to enter Control/Alt/F9 after making any changes
       in your data which will automatically refresh your workbook and update all data. 

7.  Q. Does this mean I need to check all of my Excel files to see if I have been affected
       by this?

    A. No.  Unless you have a workbook where formulas have been entered in the order
       mentioned above, you do not need to worry about this.  If you have created a workbook
       where you have used this type of formula, simply perform the workaround previously
       described.

8.  Q. How did you find out about this?

    A. This was brought to our attention by a customer in early December.  We were previously
       not aware of this error and are grateful that it was brought to our attention.

9.  Q. What versions of Microsoft Excel does this affect?

    A. This error only affects Microsoft Excel for Windows 95.

10. Q. How do I get the patch?

    A. Simply call Microsoft at (800) 360-7561 or (206) 635-7070 beginning on December
       13, 1995 and the patch will be sent to you at no charge. Or get the patch on-line
       on The Microsoft Network in the Excel Forum (GO "MSEXCEL"), on CompuServe in the Excel
       Forum (GO "MSEXCEL") and on the Internet on the Microsoft world wide web site
       (http://www.microsoft.com/msexcel).
