Portfolio Files (.mlp3)
Moneylender stores loans, payments, lender and borrower details, attached documents, and other data in "portfolio files". These files will have the ".mlp3" extension and are usually labeled as "Moneylender 3 Loan Portfolio" in Windows Explorer.
Default vs. Custom Password
Moneylender 3 has a default password hard-coded into the application that is used to encrypt portfolios. This encryption will protect the data in the file from being used by a novice hacker. If you use the default password, you should ensure the file is protected from unauthorized access, as anyone with a copy of Moneylender can open the portfolio.
Setting a custom password on your portfolio will ensure that even if the file is copied by an unauthorized person, the data is contains will be entirely inaccessible without the exact password. With a strong password (12 or more characters, capital and lowercase letters, numbers, and symbols) it would take a powerful computer multiple years to accomplish a brute-force crack and access the data. If the custom password is weak (like a word from the dictionary, or your pet's name, for example) it may be trivial for an unauthorized user to guess the password.
If the password is lost or forgotten, the entire portfolio will be completely inaccessible. You will lose all your data. There is no way to retrieve a missing password, so be very careful to ensure you don't forget the password you used to protect your data.
Should I use a custom password?
Do you feel like you have a good understanding of how someone might attack your computer and get access to your files? If so, you can probably just use the default password and keep your portfolio file safe on your computer. If you get virus and malware infections on your computer from time to time, you should use a strong custom password on your portfolio because your computer has been occasionally compromised.
Moneylender will generate an index file with the same name as the .mlp3 file, but using a .index extension instead. These index files contain the position data of the individual records in the .mlp3 file. When you close Moneylender or an open portfolio file, the index is recorded on disk so it can be read without having to traverse the entire portfolio. If the index is invalid, or out of sync with the portfolio file, it will be rebuilt.
Rebuilding an index is relatively time consuming. Portfolios with a dozen loans may only take a couple seconds to fully reindex, but portfolios with thousands of loans may take five minutes or more to reindex. It involves moving record-by-record through the file, decrypting each record, and noting the type and ID of the record and the values of fields which contains secondary indexes.
Compressing Portfolio Files
When Moneylender 3 is updated, it may include changes to the structure of the portfolio file to support new capabilities. If the program is interrupted while reorganizing the data internally, the portfolio file may become corrupted. In larger portfolios (1000 or more loans), this process can take five minutes or more.
"_backup.mlp3" Versions of Your Portfolio
Before the portfolio is restructured after Moneylender 3 is updated on your computer, a copy with of the unmodified .mlp3 file is made with "_backup(2,3,etc.)" attached to the end of the portfolio's name in the event that a power failure or other problem prevents Moneylender from completing the restructuring and compression routines. If the main portfolio is irrecoverably damaged, this backup will allow you to try the compression process again without data loss.