user129326: I'm trying to restore my old wallet which I had created on Multibit around 2016 and held a fraction of a bitcoin, as far as I can remember.
I have not touched the wallet for years until today when I found the Mnemonic words by chance. So I have downloaded the ancient Multibit client and restored the wallet. Now it is trying hard to synchronize the wallet. I have a decent laptop but the fan does not turn off while it is syncing. So I suppose there are lots of calculations involved. Though I have no clue what is that.  In any case, it is so damn slow: after several hours only 20% is synchronized. Why?
I'm wondering why does it take so long? How long should I expect for it to be fully synchronized? and how much disk space will it need?
I'm worried that it fills out laptop's 256GB SSD and still does not sync.

user5406: As far as I remember MultiBit uses BIP37 bloomfilters to request data from full nodes. BIP37 was deprecated years ago and newer full nodes no longer provide this network service. According to Luke-jr's data, there are only 662 listening nodes that still provide the "bloom" network service. 
It may be slow, because your MultiBit client is having trouble finding a decent full node to serve it data. You might be able to sidestep this issue by importing the wallet into a different wallet, or by starting up your own full node of a sufficiently old version and connect your MultiBit to that directly.

129326: <p>I'm trying to restore my old wallet which I had created on Multibit around 2016 and held a fraction of a bitcoin, as far as I can remember.</p>
<p>I have not touched the wallet for years until today when I found the Mnemonic words by chance. So I have downloaded the ancient <a href="https://download.cnet.com/MultiBit/3000-2078_4-75915646.html" rel="nofollow noreferrer">Multibit</a> client and restored the wallet. Now it is trying hard to synchronize the wallet. I have a decent laptop but the fan does not turn off while it is syncing. So I suppose there are lots of calculations involved. Though I have no clue what is that.  In any case, it is so damn slow: after several hours only 20% is synchronized. Why?</p>
<p>I'm wondering why does it take so long? How long should I expect for it to be fully synchronized? and how much disk space will it need?
I'm worried that it fills out laptop's 256GB SSD and still does not sync.</p>
 5406: <p>As far as I remember MultiBit uses BIP37 bloomfilters to request data from full nodes. BIP37 was deprecated years ago and newer full nodes no longer provide this network service. According to <a href="https://luke.dashjr.org/programs/bitcoin/files/charts/services.html" rel="nofollow noreferrer">Luke-jr's data</a>, there are only 662 listening nodes that still provide the &quot;bloom&quot; network service. <a href="https://i.stack.imgur.com/xv9AR.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/xv9AR.png" alt="enter image description here" /></a></p>
<p>It may be slow, because your MultiBit client is having trouble finding a decent full node to serve it data. You might be able to sidestep this issue by importing the wallet into a different wallet, or by starting up your own full node of a sufficiently old version and connect your MultiBit to that directly.</p>
