If you are running PDQ Inventory 1.0.1.0 you may get the following error:

Error : constraint failed 
Error Type : AdminArsenal.Foundation.SqliteConstraintException 
License Mode : Free 
Memory : 4 GB (2 GB free) 
Product : PDQ Inventory 
Subject : PDQ Inventory Diagnose Report 
Version : 1.0.1.0 
Windows : Microsoft Windows 7 Enterprise (6.1.7601.65536)

constraint failed 
Error Number: 19 
Error Code: SQLITE_CONSTRAINT 
SQL: insert into LocalGroupMembers (ComputerId, GroupName, UserDomain, UserName, IsLocal) values (@0,@1,@2,@3,@4) 
Computer Name: <name withheld>
Scan Profile: Standard 

This has now been fixed. Please download the latest PDQ Inventory to resolve this issue. (Version 1.0.2.0 is the minimum version needed)

www2.adminarsenal.com?download-pdqinventory