1. Each Gmail Keeper backup archive (zip file) has the following limits:
Can only store maximum 65,535 EML files;
The maximum size of the backup archive is 4 GB.
Note this is the not the size of emails being compressed which varies depends on the data of the emails, however, a 4GB zip archive normally contains approximately 8GB data unzipped.
How to solve the problem? It's quite easy.
You can create multiple backup profiles for a single Gmail account, and set any of the following limits for each profile:
Limit the backup to a specific date range; Or
Backup only a limited amount of folders/labels.