Posted a question in the General Discussion thread about reverting to V21. I have successfully accomplished that, but have encountered a new set of problems. Basically, I have a project that was originally created in V21. I upgraded to V22. I opened the major assembly file and created (3) pkg files, one for each configuration. I saved the assembly on exit. Note to self, create package files before upgrading. I first encountered problems with V22 while editing a separate drawing file of a constituent part. I was adding a detail view and all was fine until I changed the layer of the box around the target area. Then my title box text disappeared. There was other odd behavior as well. I exited the drawing without saving. Next I tried to open the main assembly drawing that consists of plan, elevation, section and isometric views and the BOM. Alibre encountered several errors during the "open" process (I have forwarded the error text details to support). The drawing did open, but would not fully refresh, as all views remained red. I bailed on V22 and have reverted to V21. I have confirmed that ALL constituent parts and associated drawings are still fully accessible / editable with V21 both by actually opening/closing the files and by file date, which are all prior to the upgrade date. The problem is with the main assembly file, which will not open with V21 because I opened and saved while using V22. To repeat, the ONLY file saved while using V22 was the ad_asm file. ALL ad_prt, ad_drw and ad_bom files are all still V21. The ad_drw & ad_bom files for the assembly will not open successfully because they cannot access a V22 ad_asm file. I'm sure that there is no recovery option available for opening a V22 package with V21. I can recreate the major assembly and 3 drawing files (4 sheets) which will be painful enough. I just need to be sure that I don't mess up the relationship between the constituent parts and 6 drawing files, totaling 31 drawing sheets. If I rebuild and save a new assembly as new.ad_asm, is it possible to Save As old.ad_asm (over writing V22 assembly file), without messing the constituent and associated drawing files? If so, is there any hope of "recovering" the 3 major assembly drawings even though I used the dreaded Save As command? I need to make some changes to the assembly model and in turn the associated drawings, both at assembly and part levels. What are the safest and most efficient steps that I should take to accomplish the tasks at hand? Thanks in advance!