TNG will auto purge calls when 99% call capacity is reached. It will however only purged down to 80% available. This process will not remove all your calls.
NOTE: TNG is a 32-bit application that can run on 64-bit. Ensure that your call capacity allocation is set so that TNG does not exceed the 2 GIG limit for 32 bit applications. For more details see forum post: How many calls can my TNG handle?
Possible reasons:
- If the PC was switched off / reset on the power button or you had a power failure / power dip while details was added to the file, then you can loose the file. This is the same for any application running on Windows.
- If an anti-virus program see the file as a treat, it can remove it.
- You can also ask IT side to scan you memory and harddrive for any issues to ensure it is not hardware related.