fatal error saved objects migration

[tranquilo42]

**Kibana version:**7.6.2

**Logstash version:**7.6.2

**Elasticsearch version:**7.6.2

**Server OS version:**CentOS 7

Browser version:-

Browser OS version:-

**Original install method (e.g. download page, yum, from source, etc.):**yum

**Describe the bug:**Kibana crashes after update

Steps to reproduce:

1. yum update -x kibana -> everything is fine
2. yum update kibana -> fatal error

Expected behavior: update works

Screenshots (if relevant):

Errors in browser console (if relevant):

Provide logs and/or server output (if relevant):
{"type":"log","@timestamp":"2020-04-21T12:39:37Z","tags":["fatal","root"],"pid":5109,"message":"{ Error: Document "default" has property "space" which belongs to a more recent version of Kibana (6.6.0).\n at props.find.p (/usr/share/kibana/src/core/server/saved_objects/migrations/core/document_migrator.js:249:27)\n at Array.find ()\n at nextUnmigratedProp (/usr/share/kibana/src/core/server/saved_objects/migrations/core/document_migrator.js:235:21)\n at applyMigrations
(/usr/share/kibana/src/core/server/saved_objects/migrations/core/document_migrator.js:166:18)\n at DocumentMigrator.transformAndValidate [as transformDoc] (/usr/share/kibana/src/core/server/saved_objects/migrations/core/document_migrator.js:151:43)\n at DocumentMigrator.doc
(/usr/share/kibana/src/core/server/saved_objects/migrations/core/document_migrator.js:47:19)\n at rawDocs.map.raw
(/usr/share/kibana/src/core/server/saved_objects/migrations/core/migrate_raw_docs.js:46:12)\n at Array.map ()\n at migrateRawDocs (/usr/share/kibana/src/core/server/saved_objects/migrations/core/migrate_raw_docs.js:40:18)\n at migrateSourceToDest
(/usr/share/kibana/src/core/server/saved_objects/migrations/core/index_migrator.js:212:89)\n at process._tickCallback (internal/process/next_tick.js:68:7)\n data:\n { type: 'space',\n id: 'default',\n attributes:\n { name: 'Default',\n description: 'This is your default space!',\n color: '#00bfb3',\n disabledFeatures: [],\n _reserved: true },\n references: [],\n migrationVersion: { space: '6.6.0' },\n updated_at: '2019-09-19T12:37:49.101Z' },\n isBoom: true,\n isServer: false,\n output:\n { statusCode: 422,\n payload:\n { statusCode: 422,\n error: 'Unprocessable Entity',\n message:\n 'Document "default" has property "space" which belongs to a more recent version of Kibana (6.6.0).' },\n headers: {} },\n reformat: [Function],\n typeof: [Function: badData] }"}
Any additional context:
I try to update elkstack 7.5.1 to 7.6.2. Everything works - except for the kibana update
Input through logstash comes from syslog (Linux, etc.) and winlogbeat 7.4 (Windows)
Updating the test system works (same platform and versions), but it doesn't have all data (25million vs 220million documents).
My guess is there is something in the data, that can''t be migrated, but where to find that?
And why is version 6.6.0 mentioned in the error? The system was a new 7.4 install in the beginning.
Any help would be appreciated!
Thxs
tranquilo42

[elasticmachine]

Pinging @elastic/kibana-platform (Team:Platform)

[pgayvallet]

Caused by #56731.

In this specific case, it seems like the space plugin was enabled at some point but disabled during the migration.

[tranquilo42]

Thanks a lot, that was it!

I removed xpack.spaces.enabled: false from my kibana.yml, now it works.
Unfortunately i cannot disable spaces anymore (since we don't use it), but that's mainly an optical problem.

Thanks again, great support!