Update: User data stored at Megaupload's US hosting providers could be safe for another two weeks, according to the file sharing site's legal counsel, Ira Rothken.
The lawyer tweeted today that the data would be preserved for "additional time" while the site works with US authorities on the pending legal case.
Federal prosecutors in the US have given Megaupload's web hosts the go-ahead to delete its massive trove of data as early as Thursday.
The erasure may go ahead on the basis that authorities had completed their search under the warrants, which no longer gave them a right to access that data and cleared the way for the service providers to do what they wanted, according to the Associated Press.
A letter filed last Friday by the US Attorney's Office for the Eastern District of Virginia permitted Megaupload's US hosting providers Carpatha Hosting and Cogent Communications to delete the data.
Authorities had copied data from the servers, but did not physically take them.
Together the web companies host 25 petabytes (25 million gigabytes) of Megaupload's files. If deleted, it could impact at least 50 million users, Megaupload's US lawyer, Ira Rothken told AP.
Rothken said Megaupload was working with prosecutors to prevent that data from being erased, noting the impact to customers but also its own legal defence.
Rothken pointed out that the companies holding the data were typically paid a fee. However, Megaupload's funds were frozen by the US Government.
Although Megaload's storage costs remain unknown, the cost of hosting that amount of data would be significant.
For a rough comparison, Amazon's S3 storage service costs 5.5 cents per GB for anything over 5 petabytes of storage, which would put Megaupload's monthly fees at $1.4 million - a cost that its hosts now need to decide whether is worth carrying for a customer whose funds have been seized.
During police raids across the globe last weekend, authorities seized $48 million in Megaupload assets.
Since the closure of Megaupload, its website has been replaced with an FBI copyright breach warning.
The clearance to delete the data comes days after the Pirate Party of Catalonia launched a bid to begin a class action against the FBI for allegedly breaching Spanish laws with the Megaupload shutdown.
Although the fate of Megaupload's data is not yet known, US security and privacy researcher Christopher Soghoian asked why Megaupload's users are likely to lose their data while online poker players caught out in last year's FBI raids were able to cash out their earnings.
"After the FBI raided illegal poker sites, US users were still able to cash out their accts. Why can't megaupload users cash out their data?," Soghoian tweeted.