Guide problem

[need answer]

I design motifs for a computerized quilting machine. These are all line oriented (no fills or fancy work). In the process I use a lot of guides lines to align elements of the design. I also use many layers for various parts of a design. Some of these layers are strictly for guide lines and titled "Guides". These guide layers can be moved (or used to be able to be moved) to be under my drawing lines and very convenient for drafting the design.

Sept. 11, 2025, I updated Illustrator. ALL my guides (no matter where I drag the guide layer are on top of my drawn line. This is very distracting and really complicates the design process.

I need to know if this is how any guide lines will now be oriented or if this is a bug. Is this related to "snapping" updates that came with the recent program changes.  Is there a way to get back the ability to develop guide layers so they can be dragged below my drawing lines? Is anyone else experiencing this problem?

[Jacob Bugge]

need answer,

A few questions, hopefully to give a solution:

Have you kept the previous version, and did you have customized preferences?

If you have it still, what happens if you try with that?

If you no longer have the previous version, what happens if you reinstall it and try?

[Ton Frederiks]

If I open an older version of Illustrator (I tried 2023), the guides are always on top.

Only the grid has the Preferences option to display in the background.