If you want to simply check the wallet contents... Just export the addresses from the wallet, Don't tick the "private key" box... Just select "Address String" and "Include unused"...
Then use a block explorer like block cypher, btc.com, blockchain.com etc to see if the addresses show any transaction history/balance.
Alternatively, you could simply copy/paste all the exported addresses into Electrum and it will find all the transaction history/balances for you.
By using addresses only, you'll create a "watching only" wallet in Electrum, your private keys won't be exposed and you won't need to worry about any coins be stolen etc.
When creating the Electrum wallet, simply use the "import Bitcoin addresses/private keys" option during setup...
https://bitcoinelectrum.com/files/2017/06/electrum-import-privkey-1-1.png