Cannot Change or Delete Constraints in Solver

This article was previously published under Q124499
This article has been archived. It is offered "as is" and will no longer be updated.
SYMPTOMS
In Microsoft Excel 5.x, when you try to change or delete the constraints inthe Solver model, you may receive an error message. If you change theconstraints, you may receive the error message:
Solver: An unexpected internal error occurred, or available memory was exhausted ($C$187). Please verify that your model is correctly entered and all cells contain numeric values.
If you try to delete the constraints in the Solver model, you may receivethe error message:
Run-time error '13':
Type mismatch
In Microsoft Excel version 7.0, when you try to change a constraint in yourSolver model, you may receive the following error:
Solver: An unexpected internal error occurred, or available memory was exhausted ($C$191). Please verify that your model is correctly entered and all cells contain numeric values.
CAUSE
You may receive these error messages for any/all of the following reasons:

  • The worksheet has been changed: cells have been moved, added, or deleted. The model will be trying to use incorrect cells, and it will not let you change or delete the constraints. -or-

  • You are using defined names in the cells that are set to change in the Solver Parameters dialog box. -or-

  • You are using defined names for cells used in your constraints.
WORKAROUND

Method 1

If the worksheet has been changed, the only way to resolve this problem isto copy all the data to a new sheet, and rebuild the model (constraints) inthe new sheet.

Method 2

If you are using defined names, do the following to change or deleteexisting constraints in your Solver model:

  1. If you are currently in the Solver Parameters dialog box, click Close.
  2. Delete any defined names for the cells used in the Solver Parameters dialog box.
  3. On the Insert menu, click Name, and then click Define.
  4. Select the relevant defined name, and click Delete.
  5. Repeat step 2 for each defined name that needs to be deleted.
  6. In the Define Name dialog box, click OK.
  7. On the Tools menu, click Solver.
  8. In the Solver Parameters Dialog box, click Change or Delete.
You should now be able to change or delete constraints.
STATUS
Microsoft has confirmed this to be a problem in the Microsoft productslisted at the beginning of this article.

The problem of Deleting a constraint that uses a defined name has beenfixed in Microsoft Excel for Windows 95 version 7.0. But, you may stillreceive an error in this version of Microsoft Excel if you try to Change aconstraint that is using a defined name.
REFERENCES
"User's Guide," version 5.0, Chapter 29, "Using Solver to AnalyzeMultiple-Variable Problems," and Chapter 30, "Examples of Using Solver"

For more information about Solver, choose the Search button inHelp and type:
Solver Constraints
5.00a 5.00c XL
Properties

Article ID: 124499 - Last Review: 01/11/2015 15:37:52 - Revision: 1.3

Microsoft Excel 95 Standard Edition, Microsoft Excel 5.0c, Microsoft Excel 5.0a for Macintosh

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