If you don't have space to run a full node with all the block data... running a pruned node and working with old wallets is going to be very frustrating!
Every time you want to open an "old wallet" that was last used from outside of the time period that match the blocks still on your disk, you'd need to redownload the entire blockchain again. This can take many hours, if not many days
The ideal solution is a full, unpruned node.
If you absolutely need to run it pruned, then you might want to edit the bitcoin.conf file (or start from the commandline) and pass in the
-wallet parameter as many times as necessary to open all of your old wallets at once.
-wallet=
Specify wallet path to load at startup. Can be used multiple times to load multiple wallets. Path is to a directory containing wallet data and log files. If the path is not absolute, it is interpreted relative to . This only loads existing wallets and does not create new ones. For backwards compatibility this also accepts names of existing top-level data files in .
For example, if you had the following wallet files:
old_wallet.dat
wallet_2015.dat
my_wallet.dat
You could start Bitcoin Core:
G:\Bitcoin\bitcoin-qt.exe -wallet=old_wallet.dat -wallet=wallet_2015.dat -wallet=my_wallet.dat
I get this error when I try to rename the exe to add -reindex.
You don't rename the .exe file... you "append" the
-reindex parameter to the end of the command... You either need to create a shortcut to the bitcoin-qt.exe and then edit the properties for the shortcut to change the "target" like so:
NOTE: make sure that the path to the bitcoin-qt.exe and the "start in" are relevant to YOUR setup... Based on your screenshot, I would guess instead of C:\Program Files\Bitcoin... it should be G:\Bitcoin for your setup.
Alternatively, just launch it from a "Command Prompt" window (Start, type: cmd)... then enter this command:
G:\Bitcoin\bitcoin-qt.exe -reindex -wallet=OldWalletFileName.dat -wallet=OtherOldWalletFileName.dat
That'll start up Bitcoin Core GUI, opening your old wallet.dat files... and start the reindexing process... This will likely require downloading and validating the entire blockchain again... but when it's finished, all the old wallet.dat's that you open should be "synced" and ready to use.