I have been using the trace tool to do some screen digitizing for a few weeks. Two days ago the use of the trace tool causes a crash and then this message "an unhandled win32 exception occurred in ArcMap.exe " . I need to get this thing working again. All other line editing seems to work. What is the fix?
There's always some standard fixes such as moving the layers into a new project for editing, and doing so with as few other layers as possible, checking geometry, renaming your template (normal.mxt) and seeing if a new one works (and if not going back to the old to preserve customizations) to resetting your entire application profile: http://forums.arcgis.com/threads/90076-Resetting-your-ArcGIS-application-profile.
I'll often prefer to edit lines, which allows me to copy and paste instead of tracing, (other line edits like extend or trim are also easier), and then build polygons (using points for attributes) mimicking the old coverage model and providing perfect fabric topology.
Try it again on the same section of feature in a brand new MXD and use the same features to try and duplicate it.
If it does not crash you may have an issue with the MXD you are using.
If this is the case recreate your MXD by using the Select Elements tool in Layout View. Select all elements and COPY. in a new blank MXD layout view move the existing data frame out of the way. set your page size to what it was in the original mxd, if you had set up the layout for printing. Paste to copied elements. and save your mxd.