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Some possible culprits:

1) The measures must be fully empty.

If the measures display whole rests, they may contain real whole rest, and thus be non-empty.

Delete that whole rest (so that the measure only displays a default whole rest), and the measure will be fully empty.

Fortunately you can use the plug-in to change all real whole rests to default whole rests:

Plug-ins menu > Note, Beam, and Rest Editing > Change to Default Whole Rests

2) In the Measure Attributes there is an option to break a multimeasure rest.

To de-select this option everywhere:

Measure Tool.

Select All.

Double-click the selected.

In the Measure Attributes, de-select the option Break a Multimeasure Rest.

3) The culprit could be in the Staff Tool.

Certain types of Alternate Notation will prevent multimeasure rests:

Slash Notation

Blank Notation

One-Bar Repeat

Two-Bar Repeat

4) Also, the culprit could be in the Expression Tool.

Some expressions are defined to Break Multimeasure Rests.

Examine the expression’s definition in the Expression Designer, in the chiclet Positioning.

Also look in the Category Designer (Document menu > Category Designer…)

Plug-ins menu > Note, Beam, and Rest Editing > Change to Default Whole Rests 

It will not let me default whole reets?  I only has an option to select Patterson note and beams..?

none of these seem to work..THanks anyway

Then a lot of plug-ins are missing in the sub-menu for Note, Beam, and Rest Editing.

Try a re-install of Finale v25.

Will this reinstall my saved files?

… Will this reinstall my saved files? …

By your words “my saved files” you mean your various Finale documents (scores) - right?

No, a re-install of the Finale program will not affect your Finale documents.

In case you are worried, make a backup of your Finale documents before you re-install.

How many measure are we talking about? In your part select just one measure and hit the delete key. Now do that for a couple more and see if you can now create a multi-measure rest in just those measures. If it now works, the measures did have something in them.