After using the software several times, performance may slow down.
It could be due to the state of the archives.
You can compact them using the following UNILAB tool:
https://downloads.unilab.eu/Files/Extra/DBCompact.zip
To use it, please follow the below steps:
1 - Download the compressed file
2 - Decompress into a folder
3- Open the folder and run the tool "DBCompact.exe"

4 - Set the path of the application or click on the button "..."

5 - Select the program and click on "OK":

6 - Click on "Compact databases"

7 - Be sure that all UNILAB applications are closed

8 - If all databases are compacted with success, you will see the following message:
