There is no hard-coded limit to the number of files or emails that the X1 Professional Client can index.
However, we have determined that users typically begin to experience lockups and/or performance problems when indexing reaches ~1.5 -2 million total items. Of course, this number can vary depending on types and file sizes of the items being indexed. You can determine the number of items in index by selecting the "All" search tab and looking down in the lower, left-hand corner. You should see two sets of numbers (i.e. 1 of 100,000), with the second number representing the total number of items residing in index.
As far as work-arounds go, here are several possible options to help limit the size of the X1 index (listed in preferential order):
1. Limit the number of items being indexed:
a. If you don't need to index certain directories, you can exclude them by going to Tools > Options > Files > More Indexing Options and
de-selecting them in the "Choose A Folder" section.
b. Limit the number of Outlook items from being indexed by reducing the number of folders, mailboxes and/or PST
files that you have selected for indexing using the Tools > Options > Email > Outlook > Select Folders To Scan
For files, you can also limit the level of indexing performed by indexing only file names, date/time, and size, but not the content of the files.
1. Select the level of indexing in Tools > Options > Files > More Indexing Options and choose "File names and sizes only" in the legend on the
2. Limit the maximum file size that is indexed for content. You can control this option from Tools > Options > Files > More Indexing Options.
a. Change the default 60 MB size to a smaller number. Lowering this number will affect not only files, but also email attachments.
b. If possible, confirm that the option "Keep copies of email in index" is not selected from the Tools > Options > Email screen.