Unable to start weblogic server becuase of java.io.IOException: [Store:280036]Missing the file store file "WLS_DIAGNOSTICS000001.DAT"

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Applies to:
Weblogic: 10.3.6 and later
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Problem Summary:
Unable to start server because of java.io.IOException: [Store:280036]Missing the file store file "WLS_DIAGNOSTICS000001.DAT"

Error:
weblogic.store.PersistentStoreFatalException: java.io.IOException: [Store:280036]Missing the file store file "WLS_DIAGNOSTICS000001.DAT" in the directory "/OraclePS6/domains/osb_domain/servers/osb_server01/data/store/diagnostics"
        at weblogic.store.io.file.FileStoreIO.open(FileStoreIO.java:128)
        at weblogic.store.internal.PersistentStoreImpl.recoverStoreConnections(PersistentStoreImpl.java:435)
        at weblogic.store.internal.PersistentStoreImpl.open(PersistentStoreImpl.java:423)
...............................
Caused by: java.io.IOException: [Store:280036]Missing the file store file "WLS_DIAGNOSTICS000001.DAT" in the directory "/OraclePS6/domains/osb_domain/servers/osb_server01/data/store/diagnostics"
        at weblogic.store.io.file.StoreDir.throwIOException(StoreDir.java:173)
        at weblogic.store.io.file.StoreDir.open(StoreDir.java:83)
        at weblogic.store.io.file.Heap.open(Heap.java:290)
        at weblogic.store.io.file.FileStoreIO.open(FileStoreIO.java:117)

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Root Cause:
Either you have deleted WLS_DIAGNOSTICS000001.DAT or renamed it.

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Resolution:
Solution1: If you renamed the file then revert it to the original name.
Solution2: Take server folder backup(osb_server01) and restart it. This will work in either case.