Hi Veronique,
A Global Collection's (GC) members will be defined by the search criteria you set for it. So really, there are only two possibilities here;
- No models validly meet the search criteria of the GC any longer
- The version of Spectrum you're running may have a known issue relating to GC operation in certain circumstances that results in this.
Best way to find out which is to open a support ticket and include the Spectrum version ($SPECROOT/Install-Tools/.history file), the CAPM version and an attribute dump of a model you believe should meet the search criteria of the GC. This can be obtained as follows on the SpectroSERVER:
cd $SPECROOT/vnmsh
./connect
./show attributes mh=<Model handle of desired model> >> model.dmp