How to Permanently Delete Deleted Backups and Free Storage Space in Acronis Cyber Protect Cloud

Administrators using Acronis Cyber Protect Cloud often notice that cloud storage space remains occupied even after backups are deleted. This behavior is intentional and is usually caused by immutable backup retention, a security feature designed to protect data from ransomware, accidental deletion, and insider threats.

This article explains why deleted backups still consume space, how immutability works at a technical level, and what actions administrators can and cannot take to reclaim storage safely and correctly.

Product Feature Overview

Key Features Relevant to This Topic

• Immutable Backups (WORM Storage)

  • Prevents modification or deletion of backups for a defined period

• Soft Delete Mechanism

  • Deleted backups are hidden but not physically erased immediately

• Retention Policies

  • Controls how long backups are stored

• Encrypted Storage

  • AES-256 encryption for all backup data

• Ransomware Protection

  • Ensures compliance with cyber-resilience best practices

Technical Explanation: Why Deleted Backups Still Occupy Space

Understanding Backup States in Acronis

When a backup is deleted from the console:

1. Catalog metadata is removed

2. Backup blocks remain stored if immutability is active

3. Storage is released only after the immutability lock expires

From your backup details:

deleted_immutable = true
immutable_size > 0
marked_for_deletion = false

This means:

• The backup is logically deleted

• The data blocks are cryptographically locked

• Permanent deletion is not allowed yet

Why data_size = 0 but Storage Is Still Used

Analogy:
Index removed, warehouse sealed.

Use Cases

Common Scenarios

• Cleaning old ERP or Tally backups

• Reducing cloud storage billing

• Removing decommissioned servers

• Investigating “storage not freeing” complaints

• Auditing backup retention policies

Step-by-Step: How Deletion Actually Works

Step 1: Identify Deleted but Locked Backups

1. Go to Backup Storage → Locations

2. Disable Hide deleted

3. Select the deleted backup

4. Open Details

Look for:

deleted_immutable = true
immutable_size > 0

Step 2: Check Immutability Period

Navigate to:

Backup Storage → Cloud Storage → Settings → Immutability

Note:

• Immutability duration (days)

• Applies per backup creation date

Step 3: Calculate Actual Deletion Date

Formula

Last backup creation date
+ Immutable retention period
= Physical deletion date

Until this date:

• ❌ “Delete permanently” will not appear

• ❌ Storage cannot be freed manually

What You Cannot Do (By Design)

This complies with WORM (Write Once Read Many) standards.

Security Considerations

• Immutability protects against:

  • Ransomware encryption

  • Malicious admin actions

  • Accidental deletions

• Even global administrators cannot bypass the lock

• Required for many cyber-insurance and compliance frameworks

⚠️ Disabling immutability weakens ransomware protection.

Best Practices (Highly Recommended)

For ERP / Tally / File Servers

Operational Tips

• Never re-enable old backup plans

• Review storage usage monthly

• Align retention with business RPO/RTO

• Document immutability policy for clients

Common Issues and Fixes

Issue: Storage not reducing after deletion

Cause: Immutability still active
Fix: Wait until immutability expires

Issue: No “Delete permanently” option

Cause: Backup is immutable
Fix: Not possible until lock expiry

Issue: Customer thinks storage is “stuck”

Cause: Misunderstanding of soft delete
Fix: Explain immutability lifecycle

Example (For Client Explanation)

“Your backup is deleted but protected by anti-ransomware lock.
It will auto-remove once the protection period ends.
This ensures no one—not even admins—can erase it early.”

Conclusion

Deleted backups in Acronis Cyber Protect Cloud do not immediately free storage when immutability is enabled. This is expected, secure, and irreversible by design. Storage space is released automatically after the immutability retention period expires, ensuring maximum protection against ransomware and accidental data loss.

Administrators should focus on correct retention planning, not forced deletion, to optimize storage usage while maintaining security.

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