Sounds like your file may be damaged and your backup that you are reverting to may also be damaged. (On rare occasions, damage may be hidden in your file and not affect it's function until you upgrade either FileMaker or your OS.)
Run some recover operations on your file and see what you find.
Things to keep in mind about Recover:
While Recover almost always detects and fully corrects any problems with your file...
- The recovered copy may behave differently even if recover reports "no problems found".
- Recover does not detect all problems
- Recover doesn't always fix all problems correctly
- Best Practice is to never put a recovered copy back into regular use or development. Instead, replace the damaged file with an undamaged back up copy if this is at all possible. You may have to save a clone of the back up copy and import all data from your recovered copy to get a working copy with the most up to date information possible.
And here's a knowledgebase article that you may find useful: What to do when your file is corrupt (KB5421).
As per Forum moderators, I am posting my strategy to solve this problem
Two files converted from FMP Advanced V. 11 to V.12 began to crash when I selected Set Tab Order. I am currently running V. 12.04.
I followed a set of instructions posted by S. Chamblee (moderator) to 1) Save a Copy As; 2) Run Recover of File Copy; 3) Save a Clone of File Copy; and 4) Run Recover on File Copy Clone. Each generation of these files crashed with when I entered some (but not all) layouts and chose Set Tab Order.
Since my V. 11 layouts generously featured fields, buttons, tab panels, portals and other elements with "Embossed" or "Drop Shadow" line options, design features not supported in V. 12, I removed all those on one test layout. The layout, after it was saved, opened Set Tab Order properly without crashing! I worked my way through 65 layouts in one database looking for and removing all embossed and drop shadow line options, and consistently, if every line option was set to "Solid" or "None" (and the layout saved) the file did not crash when Set Tab Order was selected. Sometimes the line option was difficult to find and if I missed even one, it would still crash. If the layout did not have any embossed elements to begin with, it did not once crashed when Set Tab Order was selected.
I am posting three images.
In the first image you see the crash text boxes and the open Set Tab Order dialog box. I thought I had removed all the embossed/drop shadow settings on this layout, had saved the layout, then chose Set Tab Order. I took this screen shot because I believed I must have missed one and wanted to document the missed element for this post.
In the second image the offending element is located - the third tab panel titled "Assignments" was still set to Embossed under the line options. The first two tab panels were properly set to Solid Line but I missed the embossed setting on this and the next two panels.
In the third image, after Embossed settings are successfully removed from every element, the layout opens properly with Set Tab Order.
I don't know if Drop Shadow is a problem, but since it wasn't supported in V12 either I just removed them too.
I am using Vista Windows operating system. I was not able to reproduce the problem when I file actively use.
Second image showing the embossed element I had missed.
Third image showing Set Tab Order opening properly without crashing after the last embossed element is re-set to a line option supported in FMP 12 such as "None" or "Solid."