I have set scheduled runnig a batch file whcih indexes over 200,000 PDF files every weekend. However index creating has become failed since the week before last and not be able to create .idx files also.

The number of PDF files increases by about 100-200 during a each week, so that I suspect this problem is caused by excess of the max indexable number of PDF files.

[Questions]
1. Is there any threshold about the field of indexing?
2. Is this issue caused by intrinsic bug of Acrobat Pro DC?

[Environments]
Windows Server 2012 R2 (64bit)
Adobe Acrobat Pro DC
File Version: 15.006.30417.5399
Free Capacity of Hard Disk (C Drive): 17.3GB
Available Physical Memory: 2.37GB
Available Virtual Memory: 3.97GB

[Reference]
Creating PDF indexes
https://helpx.adobe.com/acrobat/using/creating-pdf-indexes.html