After a power outage, the vCenter filesystem is inconsistent like described here: https://knowledge.broadcom.com/external/article/338155/manually-running-fsck-on-vcenter-server.html
If the file inconsistency cannot be resolved with the above KB article, you may consider deploying a new vCenter.
vCenter 6.7
vCenter 7.x
vCenter 8.x
1. Download the vCenter installer of the required version from the Broadcom portal: https://support.broadcom.com/
2. Follow the steps in the following document to complete stage 1 of the installation: https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vcenter.install.doc/GUID-39B42E70-9241-45AA-A0FB-2F369418501A.html
3. Follow the steps in the following document to complete stage 2 of the installation: https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vcenter.install.doc/GUID-CA114526-A413-4219-9FA7-F5A9E9ACA357.html