While the Finder's Desktop database file, does keep information about icon placement within windows and on the desktop, rebuilding the desktop file will not cause any change of positioning.
The grid choice of the Views control panel has affect on the method used by the Finder in displaying a mounted volume. The Finder will always position a mounted volume Icon as if snap to grid option is chosen even if it is not. If you do have the snap to grid option selected, the Finder will position icons within the confines of the Straight or Staggered grid selection you have chosen.
We suspect the problem you are experiencing is related to other Finder Desktop Icons, of which you say there are a many. The Finder will try to show a mounted disk (volume) somewhere on its invisible grid in the column of Icons at the right-most side of the display screen working down from the top. The Finder tries to locate the mounted volume icon so that there is no overlap of names on the desktop. If the name of the disk is very long, that may cause the Finder to search further to the left to avoid overlapping existing Icons.
If there are other icons in the right most column, whether they be RAM disk, Catalog, Mailbox, server volumes, floppy disks, or any file Icons, this may force the Finder to move its search for an empty display area one column to the left and start searching from the top again, and so on further and further to the left.
One would expect the same positioning result to happen on your system, if you inserted a floppy diskette with the same name as the SyQuest cartridge or if you saved a file by that same name from an application onto the Desktop. The Finder's Icon positioning algorithm for the Desktop includes avoiding overlap with existing neighbor Icons.
Suggestions:
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Step 1
Clean out the right most column of icons to make room for mounted volumes.
Step 2
Examine the next column to the left for files with long names. Shorten
their names or move them further to the left, so their names do not extend
into the right most column.
Step 3
Shorten the name of the SyQuest volume name.
Some combination of the above steps should clear up this situation.
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