my toolbox of modelbuilder models does not open and is now only 2 KB, can I repair a

Discussion created by on Feb 7, 2014
I was working in ArcGIS 10.2.1 and was suddendly getting some very odd I/O errors on models that had run before.  So I decided to close ArcGIS and Reopen.  When I did, the custom toolbox was gone from my ArcToolbox.  Other custom toolboxes were there.  When I try to Add Toolbox nothing happens.  I have a several day old backup of the toolbox, and it is 57 MB.  The current one, that is not opening, is 2 KB.  Where did it go?  can I repair a corrupted .tbx  . Has this happened to anyone else? Shold I make my toolbox smaller to avoid this problem again?