https://gitlab.synchro.net/main/sbbs/-/issues/493#note_3071
`smbutil p' repaired the message base for me:
```
$ smbutil p dovenetsyncprcv
SMBUTIL v3.19-Linux master/d797b7598 SMBLIB 3.00 - Synchronet Message Base Utility
Opening dovenetsyncprcv
dovenetsyncprcv locked successfully
Packing dovenetsyncprcv
Analyzing data blocks...
Analyzing header blocks...
Compressing 7928 data blocks (2029568 bytes)
and 4 header blocks (1024 bytes)
duplicate index
...
duplicate index
17592 of 17592
Done.
dovenetsyncprcv unlocked successfully
rswindell@git ~/tmp $ chksmb -e dovenetsyncprcv
CHKSMB v3.19-Linux master/d797b7598 SMBLIB 3.00 - Check Synchronet Message Base
Checking dovenetsyncprcv Headers
100%
Checking dovenetsyncprcv Data Blocks
100%
Checking dovenetsyncprcv Index
100%
Checking dovenetsyncprcv Hashes
100%
Status Total (=): 17592
Total Indexes (=): 17592
Active Indexes (=): 17592
Active Headers (=): 17592
Active Header Blocks ( ): 41772 10,693,632 bytes used Active Data Blocks ( ): 50881 13,025,536 bytes used Header Records ( ): 17592
Deleted Indexes ( ): 0
Deleted Headers ( ): 0
Deleted Header Blocks ( ): 0 0 bytes used Deleted Data Blocks ( ): 0 0 bytes used Oldest Message (import) ( ): 3820 days (0 max)
Largest Message (data) ( ): 100778 bytes (#12451)
dovenetsyncprcv Message Base is OK
---
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