One of the most frustrating issues when working with Mexico’s IMSS SUA (Sistema Único de Autodeterminación) payroll software is when you need to restore a database backup and the process fails with an error. This problem commonly occurs after formatting a computer, migrating to a new workstation, or simply trying to recover data from a previous period. This guide walks you through diagnosing and fixing the most common SUA backup restore errors.
The Error
When attempting to restore a backup from the Utilerías > Restaurar respaldo menu in SUA, the system displays one of the following error messages:
- “Error al restaurar la base de datos. El archivo seleccionado no es válido o está dañado.” (Error restoring the database. The selected file is not valid or is damaged.)
- “No se puede abrir la base de datos.” (The database cannot be opened. It may not be a database recognized by your application or the file may be damaged.)
- “Error 3343: El formato de la base de datos no es reconocido.” (Error 3343: The database format is not recognized.)
The error appears right after selecting the backup file (.mdb) and clicking the Restaurar (Restore) button. SUA displays the message, cancels the operation, and the database remains unchanged.
This issue affects all SUA versions, from 3.5.x through the latest releases, and is especially common when the backup was generated with a different version than the one currently installed.
Root Cause
There are several reasons why SUA cannot restore a database backup:
Corrupt .mdb file: The most frequent cause. The backup file became corrupted during copying, due to a power failure during the backup process, virus infection, or storage on damaged media (defective USB drive, scratched CD).
SUA version incompatibility: If the backup was generated with a different SUA version than the one installed, the database schema may be incompatible. For example, a backup from SUA 3.5.1 might not restore correctly in SUA 3.6.2.
File or folder permissions: Windows may block access to the .mdb file if it was copied from another computer or downloaded from the internet. The file might have read-only attributes or be blocked by the operating system.
Missing Microsoft Access database engine: SUA uses Microsoft Jet Database Engine or Microsoft Access Database Engine (ACE) to handle .mdb files. If these components are not installed or are damaged, the restore fails.
File path with special characters: If the folder containing the backup has accents, tildes, or other special characters in its name, SUA may fail when trying to access the file.
Step-by-Step Solution
1. Verify the backup location and file
Navigate to the folder where SUA backups are stored. The default location is:
C:\SUA\Respaldos\If you configured a custom path, check in SUA: Utilerías > Configuración > Ruta de respaldos.
Verify the following:
- The .mdb file exists in the folder
- The file size is greater than 0 KB (a 0 KB file is empty or corrupt)
- Compare the size with previous working backups; if significantly smaller, it is likely corrupt
2. Unblock the backup file
If the file was copied from another computer or external media:
- Right-click the .mdb file
- Select Properties
- On the General tab, look for the message “This file came from another computer and might be blocked”
- Check the Unblock checkbox
- Click Apply then OK
Also remove the read-only attribute if it is enabled.
3. Compact and repair the database
If the file is corrupt, try repairing it with Microsoft Access:
- Open Microsoft Access (if not installed, see the Alternative Solution section)
- Go to Tools > Database Utilities > Compact and Repair Database
- In the dialog box, select the backup .mdb file
- Choose a location to save the repaired file (use a different name like
backup_repaired.mdb) - Wait for the process to complete
In newer Access versions:
- Open Access without opening any database
- Go to File > Info > Compact & Repair Database
- Select the .mdb file to repair
4. Manually restore the backup
If SUA’s built-in restore tool continues to fail, you can restore manually:
- Close SUA completely (verify it does not appear in Task Manager)
- Navigate to the active SUA data folder:
C:\SUA\Datos\ - Back up the current file before replacing it (copy it to another folder)
- Copy the repaired .mdb file to
C:\SUA\Datos\replacing the existing file - Open SUA and verify the data loaded correctly
5. Verify the restored data
After restoring:
- Open SUA and log in with your credentials
- Go to Consultas > Patrón and verify your employer records appear
- Review the transactions from the last processed period in Consultas > Movimientos
- Generate a test report from Reportes > Cédula de determinación to confirm calculations are correct
Alternative Solution
Repair without Microsoft Access
If you do not have Microsoft Access installed, download and install the free Microsoft Access Database Engine:
- Download Microsoft Access Database Engine 2010 Redistributable from the official Microsoft website
- Install the component (select the 32-bit version, since SUA is a 32-bit application)
- Restart the computer
- Attempt to restore the backup again from SUA
Direct manual file copy
If you have access to the original computer where SUA works:
- On the source computer, navigate to
C:\SUA\Datos\ - Copy the complete .mdb file to a USB drive
- On the destination computer, close SUA
- Paste the file into
C:\SUA\Datos\on the destination computer - Open SUA and verify the data
Reinstall SUA with the same version
If the problem is version incompatibility:
- Check the SUA version that generated the backup (check Ayuda > Acerca de on the original computer)
- Uninstall the current SUA version on the destination computer
- Install exactly the same version that generated the backup
- Restore the backup
- Once restored, update SUA to the latest version if desired
Prevention
To avoid future backup issues with SUA:
- Back up regularly: Generate a backup before and after each bimonthly process from Utilerías > Respaldo
- Verify backups: After generating a backup, confirm the .mdb file has a reasonable size (several MB if you have many workers)
- Keep multiple copies: Store backups in at least two different locations (local hard drive and external media)
- Avoid special characters in backup paths: do not use accents or tildes in folder names
- Document the SUA version: Note alongside each backup which SUA version generated it
- Test restoration: Periodically restore a backup on a test installation to confirm it works
Related Issues
| Issue | Probable cause | Quick fix |
|---|---|---|
| SUA won’t open after restore | Incompatible .mdb version | Reinstall the same SUA version that generated the backup |
| ”threed32.ocx” error when opening SUA | Unregistered OCX component | Register the component with regsvr32 threed32.ocx from CMD as administrator |
| Database locked by another user | .ldb file present in the folder | Close all SUA instances and delete the .ldb file |
| Backup generates a 0 KB file | Full disk or permission error | Check available disk space and write permissions on the destination folder |
| IDSE connection error | Expired digital certificate | Renew the digital certificate from the IMSS portal |
Summary
- SUA backup restore errors are usually caused by corrupt .mdb files or version incompatibility
- Always verify the backup file size before attempting to restore
- Use the Microsoft Access Compact and Repair tool to recover damaged files
- Manual restoration by copying the .mdb file directly to
C:\SUA\Datos\is a reliable alternative - Keep multiple backups in different locations and document the SUA version used
- Install Microsoft Access Database Engine 2010 (32-bit) if you don’t have full Access