Akeeba Backup 3.4.x is designed to run only on Joomla! 1.5 and 2.5. It's not tested on Joomla! 1.7 and I don't know if it will work or not. Also note that since April 1st we have dropped support for Joomla! 1.6 and 1.7. Right now, these Joomla! versions have known very high priority security vulnerabilities and they are not supported by the Joomla! project (they are end of life). We can not support insecure, outdated, end-of-life releases of Joomla!. If you want, you can install version 3.3.13 on your site, but please note that both this version of Akeeba Backup and this version of Joomla! are not supported.
That said, I can reply regarding the System Restore Points (SRP) feature's design goal and its pros and cons. SRPs are supposed to be small backups of just an extension (module, plugin, component or template), taken automatically whenever you update that extension. The major problem is that there is no official convention on the naming of the database tables used by each extension, or where it stores all of its files. As a result, it is impossible to create an 100% accurate SRP solution. Our SRP feature will try its best to take a backup, in hope that if the extension update fails you can restore this "mini backup". It may or may not work. It is advisable to always have a full site backup and rely on it.
In other words, restoring an SRP backup should be your first attempt to resolving a broken extension. If that doesn't work, you should restore a full site backup. Restoring an SRP can be done through the Akeeba Backup, Administer Backup Files, Restore Points page. The procedure is documented and it consists of pretty much clicking on the Restore button in the right-hand column of the SRP backup.
Please always keep in mind that SRP backups should not be relied upon as your one and only backup policy. They are not designed to fulfil such a role. At all times, I strongly recommend having regular, off-site stored, tested full site backups. SRPs are like airbags: they can provide additional protection, but you should not use them without a seatbelt expecting them to save you from a crash (in this analogy, full site backups being the seatbelt).
Nicholas K. Dionysopoulos
Lead Developer and Director
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