Hello. I am a long time user of X1 (since version 2.0).
I am still using daily my old X1 Desktop Search Version 5.2.3 (Build 1852bz-bs) (Released Friday, August 26, 2005), running on Windows 8.1 and indexing about 2,000,000 files (about 4 TB of data) on several volumes (internal drives, USB drive, NAS).
I have kept this version because after version 5.2.3, X1 began to deal with the accented letters in a bad way (I have written several posts on this subject on the X1 forum). And when finally X1 got a satisfactory way to deal with accented letters, X1 lost the ability to index Thunderbird email, which is incompatible with my use.
But more and more frequently, I realize that X1 misses some of my files. Sometimes it is solved by re-indexing (it takes around 36 hours), but some files refuse to be indexed for an unknown reason...
By the way, I do not trust X1 searches any longer, and I am looking at some other solutions.
I have found this forum today, and there are interesting discussions here.
That is why I post this message here, in order to follow these discussions.