It is an old wallet. Rescan begins from block 0, so it is completely not scanned.
Yes, Bitcoin Core is fully synced. Full-node.
I know nothing about this wallet. It size is 88 kB (90112 B).
Seems like it can be wallet without any private keys (see logs below).
Also no version of this wallet is given in logs, which is very strange.
I close all wallets and open only this one from menu.
I don't know if it is encrypted. There may be no private keys so there could be nothing to encrypt.
It does not randomly crash - it does crash when finishing rescan, at 100%.
I suspect it can be forged wallet, as any wallet cannot have rescan at block 0. Minimal chance for any wallet.
When opening the wallet I get in logs (started with -debug=1):
2022-08-02T08:07:19Z Using wallet h:\blockchain\129 88k crsh\wallet.dat
2022-08-02T08:07:19Z BerkeleyEnvironment::Open: LogDir=h:\blockchain\129 88k crsh\database ErrorFile=h:\blockchain\129 88k crsh\db.log
2022-08-02T08:07:19Z init message: Loading wallet…
2022-08-02T08:07:19Z [129 88k crsh] CDataStream::read(): end of data: iostream error
2022-08-02T08:07:19Z [129 88k crsh] CDataStream::read(): end of data: iostream error
2022-08-02T08:07:19Z [129 88k crsh] Wallet completed loading in 10ms
2022-08-02T08:07:19Z init message: Rescanning…
2022-08-02T08:07:19Z [129 88k crsh] Rescanning last 747619 blocks (from block 0)...
2022-08-02T08:07:19Z [129 88k crsh] Rescan started from block 000000000000000000cd74d3024470a4e206096e3a6ce5091bcfae787d5d32df...
When Bitcoin Core crashes I get in logs:
2022-08-02T08:52:10Z [129 88k crsh] Rescan completed in 2691375ms
2022-08-02T08:52:10Z [129 88k crsh] setKeyPool.size() = 100
2022-08-02T08:52:10Z [129 88k crsh] mapWallet.size() = 2
2022-08-02T08:52:10Z [129 88k crsh] m_address_book.size() = 1
2022-08-02T08:52:10Z TransactionAddedToMempool: txid=5c038f0c544e283e3588fa7daecdc6d29cf78e66cf4dde02aa78fa798e8eadca wtxid=282df781a2deb15d524e1c1b1d77bb44034b8ddc3ab9102f3847c5dd61153882
Nothing more. -debug=1 was used.
I cannot do further tests, if you want - you can, I can share the wallet.
Idea of my thread is to fix Bitcoin Core from crashing, not repairing the wallet.