BugZero | F5 BugID 734557 - BIG-IP fails to load MCPD due to empty bigip.conf ...

F5 - Defect ID: 734557

BIG-IP fails to load MCPD due to empty bigip.conf after the UCS save/load and reboot

F5 - Defect ID: 734557

BIG-IP fails to load MCPD due to empty bigip.conf after the UCS save/load and reboot

Last updated on May 5th, 2026

BugZero Risk Score
8.7 High

Overall: 8.7

Severity: 9.1

Community: 4.2

Lifecycle: 10.0

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Bug Details

Priority: 2-Critical
Status: Resolved
Impact Category: TMOS

Description

Symptoms

After saving/loading the UCS and rebooting, the BIG-IP system may end up in a state where the bigip.conf file is empty. This can cause MCPD to fail to load. Error logs have shown that MCPD is waiting without receiving a response, and the system configuration cannot be loaded due to the missed user configuration.

Impact

MCPD fails to load, causing the BIG-IP system inoperative until the configuration is restored from backup (bigip.conf.bak), resulting in downtime

Conditions

Occurs intermittently after UCS save/load operations followed by reboots or toggling the BIG-IP. The bigip.conf file ends up empty, while the bigip.conf.bak remains intact.

Workaround

None

Fix Information

None

Change history

2026-05-05 Added: 17.1.3, 17.1.3.1, 17.1.3.2, 17.5.1.2, 17.5.1.3, 17.5.1.4, 17.5.1.5, 17.5.1.6

2026-03-03 Added: 17.1.3, 17.1.3.1, 17.5.1.2, 17.5.1.3, 17.5.1.4, 17.5.1.5

2025-11-14 Added: 17.1.3, 17.5.1.2, 17.5.1.3

2025-10-15 Added: 17.1.3, 17.5.1.2, 17.5.1.3

2025-10-07 Added: 17.5.1.2

2025-07-23 Added: 14.1.0, 14.1.0.1, 14.1.0.2, 14.1.0.3, 14.1.0.5, 14.1.0.6, 14.1.2, 14.1.2.1, 14.1.2.2, 14.1.2.3, 14.1.2.4, 14.1.2.5, 14.1.2.6, 14.1.2.7, 14.1.2.8, 14.1.3, 14.1.3.1, 14.1.4, 14.1.4.1, 14.1.4.2, 14.1.4.3, 14.1.4.4, 14.1.4.5, 14.1.4.6, 14.1.5, 14.1.5.1, 14.1.5.2, 14.1.5.3, 14.1.5.4, 14.1.5.6, 15.0.0, 15.0.1, 15.0.1.1, 15.0.1.2, 15.0.1.3, 15.0.1.4, 17.1.0, 17.1.0.1, 17.1.0.2, 17.1.0.3, 17.1.1, 17.1.1.1, 17.1.1.2, 17.1.1.3, 17.1.1.4, 17.1.2, 17.1.2.1, 17.1.2.2, 17.5.0, 17.5.1

Relevant Products

Click on a version to see all relevant bugs

Affected versions:14.1.0, 14.1.0.1, 14.1.0.2, 14.1.0.3, 14.1.0.5, 14.1.0.6, 14.1.2, 14.1.2.1, 14.1.2.2, 14.1.2.3, 14.1.2.4, 14.1.2.5, 14.1.2.6, 14.1.2.7, 14.1.2.8, 14.1.3, 14.1.3.1, 14.1.4, 14.1.4.1, 14.1.4.2, 14.1.4.3, 14.1.4.4, 14.1.4.5, 14.1.4.6, 14.1.5, 14.1.5.1, 14.1.5.2, 14.1.5.3, 14.1.5.4, 14.1.5.6, 15.0.0, 15.0.1, 15.0.1.1, 15.0.1.2, 15.0.1.3, 15.0.1.4, 17.1.0, 17.1.0.1, 17.1.0.2, 17.1.0.3, 17.1.1, 17.1.1.1, 17.1.1.2, 17.1.1.3, 17.1.1.4, 17.1.2, 17.1.2.1, 17.1.2.2, 17.1.3, 17.1.3.1, 17.1.3.2, 17.5.0, 17.5.1, 17.5.1.2, 17.5.1.3, 17.5.1.4, 17.5.1.5, 17.5.1.6

Fixed versions: No known fixed versions

Relevant Products

Click on a version to see all relevant bugs

Fixed versions: No known fixed versions

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F5 - Defect ID: 734557

BIG-IP fails to load MCPD due to empty bigip.conf after the UCS save/load and reboot

F5 - Defect ID: 734557

BIG-IP fails to load MCPD due to empty bigip.conf after the UCS save/load and reboot

Last updated on May 5th, 2026

BugZero Risk Score8.7 High

Bug Details

Symptoms

Impact

Conditions

Workaround

Fix Information

Top F5 Defects

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BugZero Risk Score
8.7 High