Is this for a RIO repository? All templates, fields, entries came back but user security and groups did not?
All security settings that you mention above are stored in SQL so it should be possible. If you got documents back but not security I'd like to know more because they are stored in the same database, at least in RIO anyways.
For RIO the user information is referenced in a few tables in this repository database and gets a little messy but everything is labeled pretty well.
Group assignments/Accounts
Repository named user group membership is stored in [grouplist] and associated by "trustee_id". This is a unique ID for laserfiche based off the SID/User account or Group which leads me to the next table.
A trustee's basic information (unique laserfiche ID, SID, name, description, salted password etc) are stored in [trustee].
So when you look at [grouplist], you'll see group_id = 1008, and member_id = 7. These are both trustee_id's reference in this table. Both groups and members have a trustee_id and are referenced in the [trustee] table. This will cover group association of named user accounts but not windows accounts.
Some other basics:
If the repository named user or windows account is trusted and allowed to authenticate by user account instead of group membership they will be listed by SID in [trusted_allow].
If the member is within a trusted group, they will be listed by SID in [trusted_group] and the "trustee_id" of that trusted group will be listed as "trustee_id".
The same structure goes for those authenticating through ldap in [ldap_allow].
LDAP profiles are stored in [ldap_server_profiles].
Last login/logout information is in [user_login].
A trustee's attributes, the settings which dictate a lot of how the client interacts with the account, and are found by double clicking on a user and going to the attributes section, are all stored in [trustee_attr].
A trustees privileges, features, audit settings and read only flag is stored in. [account_security].
Access Rights - Document/Folder level security is in [entryacl] and entered 1 row per SID for each entry which has security applied.
"toc_id" is the entry id of the document.
"mask" is a numeric value for the actual security applied. IE: A value of [1] means the user only has the browser permission. A value of [1048575] means full permissions.
"ace_flags" refers to the scope I believe.
"pos" is the sequence of how they are listed in the access rights console
Tags are in [tag] and given a tag_id.
Tags associated to a trustee are stored in [trustee_tag].
Tags associated to a document are in [tagacl].
Field level security is in [propacl] and referenced by a master field id and the account's SID.
Summary
It gets pretty dirty which leads me back to the question of how were you able to get documents back but no security? It makes me believe just one table was corrupted so I'd like to know more about what is missing and what's there.
If you have all fields, templates, documents, and that all works fine and dandy but no users are in the admin console listed, I'd look at the [trustee] table. After this, if access rights aren't showing up I'd look at [entryacl].
I hope this rambling is of use, good luck!