If both of the following are true:
then the latest MS Search version you may use is 1.7a-o (file V17O_UPG.zip). In this case, using NIST MS Search v2.0 to update or create your user MS library may make the library incompatible with your (third party) software.
To resolve this incompatibility with the NIST MS Search v2.0 the third party software needs to be updated to the current version of the NISTDL32.DLL or NISTDL16.DLL.
User MS Libraries created/updated by the MS Search v2.0 may also have compatibility problems with older NIST MS Search version 1.6x. However, these libraries are fully compatible with the NIST MS Search v1.7 and are searchable with v1.7-o.